Jurgen Klopp has admitted that Liverpool must "suffer" at the hands of Barcelona if they are to stop Lionel Messi from carrying out his "threat" to bring the Champions League trophy back to the Camp Nou.

Liverpool, last season's beaten finalists, face the Spanish champions in Wednesday's semifinal first-leg after cruising past Porto in the previous round to book a place in the last four.

But after destroying Manchester United in the quarterfinals with a virtuoso performance in the home leg a fortnight ago, Messi goes into the clash with Liverpool closing in on fulfilling the promise he made to the Barca fans at the start of the season.

- Hunter: Liverpool have potential to be Barca's kryptonite

- Marcotti: Barcelona's title win about more than Messi

"Last season was really good as we did the double, but we all felt bad about how it went in the Champions League," Messi said in September. "We promise that this season we will do all we can to bring that beautiful trophy back to the Camp Nou."

And although he goes into the game having failed to manage a team to victory against a Spanish club in Spain, Klopp insists that Liverpool can overcome Barcelona and Messi despite the Argentine forward's own determination to lead Barca to glory.

"Messi said at the start of the season that they wanted to bring back this cup," Klopp said. "That sounded already like a threat to me!

"But now we are here, we want to go to the final as well.

"We won't be perfect tomorrow, we will make mistakes, we will suffer, 100 percent. It will be so difficult, but I couldn't be more excited to play and I hope I can transport my players so they feel the same.

"It is not only about Messi, but it is about Messi of course. Can we concentrate on Messi? We should, in certain moments, but then they have 10 world-class players around who can decide the game.

"They have the highest quality team, they are already Spanish champions.

"But we saw the game against Real Sociedad and [Sociedad] did really well. Levante did really well a couple of days ago.

"Barcelona, the better the opponent, the better the competition, the higher the stakes, the more they are in. They are champions of Spain, so now they can focus completely on the Champions League. We are really looking forward to it, but it will be tough."

With Liverpool hosting the second leg at Anfield next Tuesday, Klopp admits the priority is to keep the tie alive for the return fixture.

"I would say that a draw is not the worst result in the world," he said. "Not that we will go for it, but it would be OK.

"So many people came to Barcelona and had an idea on how to play, and in the end they got a proper knock, so we know how tough it will be.

"But two years ago it was a big, big thing for the club to qualify for the Champions League. Now for the second time in a row we are here in the semifinal, that's big.

"It's only positive and everybody sees it like that. We don't need a guarantee.

"But we want to stay in this competition, to get a result tomorrow that gives us a good chance to do it at home. Whatever that result is, we want it."

Liverpool, meanwhile, travelled to Spain with striker Roberto Firmino in the squad after the Brazilian missed last Friday's 5-0 win against Huddersfield with a muscle injury.

"If Bobby is 100 percent ready, then he will maybe play," Klopp said. "He's here, he trained today, we have another session tomorrow. Then I have a decision to make."

Tottenham defender Jan Vertonghen had to be helped off the field shortly after trying to continue to play following a clash of heads in their 1-0 Champions League semifinal loss to Ajax on Tuesday.

Vertonghen challenged for a header in the Ajax area just after the 30-minute mark, but slammed his face into the back of teammate Toby Alderweireld's head, leaving him with blood pouring from a cut on his nose. Vertonghen received treatment on the field and went to change his bloodied white jersey before returning to the game.

Referee Antonio Mateu Lahoz was pointing at his head as he spoke to Vertonghen, before allowing him to return to action in the 38th minute.

He didn't last long before going across to the sideline, leaning over and struggling to stand. He had to be helped down the tunnel by two medical officials and was replaced by Moussa Sissoko.

UK broadcaster BT Sport said that Vertonghen remained in the stadium dressing room after the incident and was being looked at by medical staff.

Following the match, Tottenham manager Mauricio Pochettino said of Vertonghen: "I don't know; I didn't see him. Of course, we will assess in the next few days and will see."

Multiple reports following the match said that Vertonghen passed concussion tests and was also seen walking through the mixed zone after leaving the dressing room.

When asked about allowing Vertonghen to return to the field, Pochettino said it was a decision made by the team's medical staff.

"I wasn't involved, that was a doctor decision," Pochettino said. "I think it's so important things that the rules and the protocol are there and the medical staff follow the protocol. I was never involved, the decision was the doctors and the referee then asked to put him in and said 'go in' and in this action we need to put him out because he didn't feel well.

"Tt wasn't my decision, I repeat. For me, first of all its your life. We must protect the player and of course I was out of the conversation and our medical followed the protocol and decided it was possible to restart the game and it's time to play again.

"But of course it was Jan in that moment and the following action that he started to follow unwell and we check him with the doctor."

Pochettino said he hoped that Vertonghen wouldn't have any more issues following the knock and said he appeared to look OK when he left the stadium.

"He was walking away from the stadium now," Pochettino said. "I hope he is well and you know very well that always you need to keep eyes watching him, others beside him because it was a big knock. I hope it is not a big issue but at the moment he is OK."

Ajax's Donny van de Beek grabbed an early goal to secure a precious 1-0 victory at Tottenham Hotspur in the first leg of their Champions League semi-final on Tuesday.

The 22-year-old struck in the 15th minute to give Ajax a crucial away goal and leave Spurs facing a daunting task in Amsterdam if they are to reach the final for the first time.

Ajax, having already knocked out Real Madrid and Juventus en route to their first semifinal in Europe's elite competition since 1997, were too pacey for a labouring home side, especially in a first half in which they could have put the tie to bed.

Tottenham improved after the break but Ajax defended their lead diligently to restrict the home attack and almost scored a second goal late on when David Neres hit the post.

Erik ten Hag's youthful Ajax side started the match full of energy and purpose with Spurs barely able to escape their own half as they spent the early stages chasing shadows.

Ajax showed just why they had eliminated European giants Real and Juve in the previous two rounds as they sliced through Tottenham's labouring ranks almost at will.

The visitors needed only a quarter of an hour to go ahead as Hakim Ziyech's threaded pass found Van de Beek and the midfielder calmly placed his shot past goalkeeper Hugo Lloris.

There was a suspicion of offside but unlike in Tottenham's epic quarterfinal win over Manchester City, when Raheem Sterling's stoppage-time goal was ruled out, VAR could not save the London side this time as the Ajax fans celebrated.

Van de Beek should have made it 2-0 from Dusan Tadic's pass as Ajax dominated and when Spurs defender Jan Vertonghen was replaced by Moussa Sissoko after a clash of heads with team mate and fellow former Ajax player Toby Alderweireld, it seemed nothing was going right for the hosts.

A Tottenham attack missing the injured Harry Kane and suspended Son Heung-min had looked blunt, with Spaniard Fernando Llorente wasting their best chance when he headed wide from Kieran Trippier's cross.

The introduction of midfield powerhouse Sissoko, deemed not fit enough to start, injected some much-needed energy into Tottenham and he fizzed a shot wide from Llorente's knockdown just before half-time.

Spurs pushed on at the start of the second half and finally began to test the Ajax defence by applying some sustained pressure, with the crowd packed into the stadium responding by raising the decibel-level inside their new ground.

Dele Alli, on the periphery in the first half, volleyed straight at Ajax keeper Andre Onana, then headed over the bar.

Christian Eriksen, yet another former Ajax player in Tottenham's ranks, then played in the overlapping Danny Rose but the left back's shot was charged down.

Spurs were vulnerable to the counter however and Ajax came agonisingly close to doubling the lead, and leaving Tottenham with a near-impossible task in the second leg, when Tadic linked up with Neres whose side-footed shot rebounded off the post.

Considering the way Tottenham struggled at the start of the game, they will still travel with hope next week, especially with their prolific South Korean striker Son available again.

Cricket West Indies has agreed to the BCCI's request of pushing back India's 2019 tour of the Caribbean by a couple of weeks. ESPNcricinfo understands the tour is likely to commence in the first week of August and run till September 4. The final dates for the India tour along with the venues will be finalised by CWI at its board meeting on May 13.

As per the ICC's FTP, India were scheduled to tour West Indies immediately after the World Cup for a full tour comprising two Tests, three ODIs and three T20Is. Although no dates had been finalised, it is believed that India were meant to reach the Caribbean immediately after the World Cup final on July 14. However, the BCCI might have wanted the India players to have a break before the West Indies tour, which the CWI was happy to entertain.

CWI also wanted a clear window for the Caribbean Premier League, which has now also been rescheduled, owing to the shift in the India tour itinerary. Originally, the seventh edition of the CPL was scheduled from August 21 to September 27. As per the revised dates, the tournament will now be played between September 4 and October 12.

ESPNcricinfo understands that the BCCI has requested CWI to include a three-day warm-up match during the India tour. India A will also be playing three four-day matches in the West Indies prior to the senior team's tour game. A final schedule for all the tours will be finalised at the CWI Board meeting in two weeks.

Johnny Grave, CWI's chief executive officer, said having a clear window would mean all the West Indies players would be available for the CPL. "We are pleased that we have been able to collaborate with CPL to find a spot in our international calendar to ensure that all the best Caribbean cricketers can take part, as the tournament plays a crucial role in our preparations and planning for the T20 World Cup in 2020," Grave said in a media release issued by CPL.

CPL's chief operating officer Pete Russell said the change of schedule would not hamper the tournament in any way. "The Biggest Party in Sport may have been delayed by two weeks, but it is going to be even better as a result."

Running back Jamaal Charles is set to announce his retirement from the NFL after 11 seasons and sign a one-day contract with the Kansas City Chiefs to retire with the franchise, 610 Sports Radio reported Tuesday.

Charles, 32, played nine seasons for the Chiefs after being selected in the third round (73rd overall) of the 2008 NFL draft and was a four-time Pro Bowl selection and two-time first-team All-Pro with Kansas City. He is the franchise's all-time leading rusher with 7,260 yards.

Kansas City released him in February 2017 and he played for the Denver Broncos (in 2017, appearing in 14 games) and Jacksonville Jaguars (2018, for two games) the past two seasons, rushing for 303 yards on just 75 carries.

He finishes his career with 7,563 yards, 56th on the NFL's all-time rushing list. His career average of 5.4 yards per carry is ranked first all-time among rushers with at least 1,000 carries.

Charles twice had to overcome ACL injuries, in 2011 and 2015, missing 14 games in '11 and 24 games in '15 and '16 combined. He bounced back nicely after the first ACL injury, setting his career high with 1,509 rushing yards in 2012. In 2013 he set his career high in touchdowns with 19 (12 rushing and seven receiving).

However, he was unable to fully rebound from his second ACL injury. He played just three games in the '16 season before being placed on injured reserve with knee soreness and later undergoing arthroscopic surgery.

HARRISBURG, Pa. -- A federal judge threw out former Penn State President Graham Spanier's misdemeanor child-endangerment conviction on Tuesday, less than a day before he was due to turn himself in to begin serving a jail sentence.

The decision by U.S. Magistrate Judge Karoline Mehalchick in Scranton, Pennsylvania, gave state prosecutors three months to retry Spanier under the state's 1995 child endangerment law, the version in place in 2001.

Joe Grace, a spokesman for the attorney general's office, said the decision was under review. Spanier's defense lawyer declined to comment.

Mehalchick agreed with Spanier that he was improperly charged under a 2007 law for actions that occurred in 2001, when he was responding to a complaint about former assistant football coach Jerry Sandusky showering with a boy on campus.

"Spanier submits that this retroactive application is unreasonable and far more extensive than anyone in 2001 would have been able to reasonably foresee,'' Mehalchick wrote. "The court agrees.''

Spanier had been due to report to jail early Wednesday to begin serving a minimum sentence of two months.

Spanier, 70, was forced out as Penn State president shortly after Sandusky was arrested in 2011 on child molestation charges. A year later, Spanier was accused of a criminal cover-up, although many of those charges were dismissed by an appeals court. The jury acquitted him of what remained by the time of his trial, except for the single count of child endangerment. Lisa Powers, a university spokeswoman, said Tuesday that Spanier remains a tenured faculty member on paid administrative leave.

Spanier's lawyers argued that the application of the law to acts that occurred years before the measure was passed violated the U.S. Constitution.

But the judge did not agree with their argument that the statute of limitations had been improperly applied.

Spanier was convicted for how he and two of his top aides decided to respond to a report from graduate assistant coach Mike McQueary that he had seen Sandusky abusing the boy late on a Friday night in a team shower.

Spanier has said the abuse of the boy, who has never been conclusively identified, was characterized to him as horseplay.

Spanier and two of his top lieutenants, former athletic director Tim Curley and former vice president Gary Schultz, agreed to notify The Second Mile, the charity for at-risk youth where Sandusky met many of his victims, but not to call police.

Spanier gave his approval to his deputies in an email, warning that ``the only downside for us is if the message isn't `heard' and acted upon, and we then become vulnerable for not having reported it.''

Curley and Schultz were also charged criminally for their actions regarding Sandusky, but on the eve of trial they both pleaded guilty to misdemeanor child endangerment and testified for the prosecution. Both have since served similar jail sentences.

Spanier did not testify at his trial and told the judge at sentencing that he regretted not intervening more forcefully.

Sandusky is doing 30 to 60 years in state prison and recently won an order for a new sentence.