Barcelona midfielder Arthur Melo's house was robbed and his brother was threatened with a knife on Wednesday during the Champions League win against Liverpool, sources have confirmed to ESPN FC.

Two thieves broke into Arthur's house in the Pedralbes neighbourhood of the Catalan city through a window and left with several items, including watches and objects which were easy to carry.

While they were still in the house, Arthur's brother, Paulo Henrique, arrived back from watching Barca beat Liverpool 3-0 at Camp Nou. When confronted by him, the robbers threatened him with a knife and were able to constrain him and an assistant who had also been in the property.

Once the duo had left, Arthur was contacted by his brother and told what had happened. The Brazil international raised the issue with Barcelona's security staff, who in turn contacted the police.

The police arrived at the scene later on Wednesday night and an official report was filed on Thursday.

It's not the first time a Barca player's home has been targeted in recent years. Gerard Pique, Jordi Alba, Philippe Coutinho and Kevin Prince Boateng have all suffered break-ins since 2018.

Robbers broke into Pique's house while he was attending his partner Shakira's concert in the city last summer. Coutinho, Alba and Boateng were all targeted while Barcelona matches were being played.

Arthur joined Barca from Gremio last July and has been an ever-present in Ernesto Valverde's side in his first season in Spain. However, he was the surprise omission from the team against Liverpool, with Arturo Vidal preferred over him.

Lionel Messi criticised Barcelona fans for jeering Philippe Coutinho when he was taken off in the second half of Wednesday's 3-0 Champions League win against Liverpool at Camp Nou.

Messi struck twice in the second half, bringing up 600 Barca goals in the process, to leave his side in a commanding position heading into next week's semifinal second leg at Anfield.

But Barca's win was tainted by the treatment former Liverpool playmaker Coutinho received when he was replaced by Nelson Semedo just before the hour mark. The club's record signing endured a difficult night against his ex-teammates but Messi didn't believe his performance was deserving of the whistles aimed at him by his own fans.

The Argentina international even celebrated his first goal -- which made it 2-0 in the 75th minute following Luis Suarez's opener -- by telling the home supporters not to whistle their own players.

Ogden: Liverpool made Messi angry -- they paid the price

Barcelona player ratings: Messi a perfect '10' in big win

"We're at the defining stage of the season and we have to be more united than ever," Messi told reporters after the game. "I said that at the start of the season. It's not the time to criticise anyone.

"We have to support each other and stick together for the rest of the season. It is ugly to treat a player like that when they're taken off."

While Coutinho's Camp Nou struggles endured, it was another electric performance from Messi, 14 years to the day since he scored his first goal for the club against Albacete. His second goal was a sublime free kick from 30 yards.

He now has 12 goals in Europe this season and 48 in all competitions, with Barcelona on the verge of a first Champions League final since 2015 and with a treble in their sights. They've already won La Liga and have a Copa del Rey final to come against Valencia later this month.

However, the scoreline did flatter Barca slightly. Liverpool had their chances throughout the game, with Marc-Andre ter Stegen making three good stops and Mohamed Salah missing a great late opportunity to grab an away goal when he struck the woodwork.

"We're not used to not having the ball and we struggled a little," Messi admitted. "But that's how the game went and we had to find a way through in whatever way necessary. They didn't manage to score and that's important.

"We were better in the first half and they pressed well in the second, but they didn't have too many chances. Of course, they wanted to get a goal, an away goal is huge. We have a good advantage but we know it's not over. Anfield's a really tough place to go."

Coach Ernesto Valverde also warned that the tie is far from over. Barca were knocked out in the quarterfinals last season by Roma when, despite winning the first leg 4-1, they were beaten 3-0 at the Olimpico.

"Liverpool had some clear chances -- one off the post," Valverde said in his postgame news conference. "And there was a great save by [Ter Stegen]. They had their moments and we had to suffer at times but, in the end, we got a good result against a really strong team.

"But it's a similar result to last year. We also had a three-goal lead against Roma."

Barcelona and Spain legend Xavi Hernandez has officially announced that he will retire from football after 21 years.

The Spanish national team veteran, who plays in Qatar for Al Sadd, confirmed in an open letter on Thursday that this will be his last season and that he will continue his career as a coach.

"It has been a privilege to play football up to age 39 and I would like to finish out the season on the top by winning the Amir Cup and reaching the next stage of the Asian Champions League.

"This is my last season as a player, but I really want to see what the future holds for me as a manager," Xavi, who joined Barca's senior side during the 1998-99 season, said in a letter.

The Barcelona academy product led the Catalan club to eight titles in La Liga as well as four Champions League trophies. His total silverware for club and country, 31 trophies, is a number only surpassed by his longtime Spain and Barcelona teammate Andres Iniesta.

He spoke about his developing style as a manager, citing the influence of Johan Cruyff and La Masia and the style that Barcelona gave to the world.

"I love to see teams that take the lead on the pitch, that attacking football and that return to the essence that we all know from the days of our youth, possession of the ball," he said.

"It has been a privilege to accomplish what I have done over the past two decades. And that is why I feel that it is my duty to begin an initiative on the field and give back to football as long as I am able."

Capped 113 times for Spain, Xavi played a key role in his country's 2010 World Cup victory in addition to Spain's victories at both Euro 2008 and Euro 2012. He retired from national team play in 2014.

Atletico Madrid have been confirmed as opponents for the MLS All-Star Game in Orlando on July 31, continuing the trend of an elite European team playing against the best in Major League Soccer.

"The atmosphere in Orlando will be intense and memorable when Atletico Madrid takes on the MLS All-Stars," MLS Commissioner Don Garber said.

"Atletico joins the list of the many prominent clubs in global soccer to play in our midseason showcase, and we know the passionate supporters that make up The Wall and the rest of Orlando City Stadium will provide a distinctive home-field advantage for the MLS All-Stars."

The All-Stars lost to Juventus last season and Real Madrid the previous year, with both matches decided on penalties. The 2019 event is the 16th time an elite club has played the MLS All-Stars, with Atletico the second team from La Liga to feature.

"Atletico Madrid are proud to participate in our first Major League Soccer All-Star Game and battle the many great players of MLS," club President Enrique Cerezo said.

"The U.S. and Canada have always been important markets for our club and competing in the MLS All-Star Game is an excellent opportunity to connect with our fans in North America and reach out to new ones. It will also be a great experience to play in Orlando, which has developed into a top soccer city with incredibly passionate fans since joining MLS. This is an exciting moment."

Diego Simeone's side are second in La Liga behind champions Barcelona.

The week's two Champions League semifinal first legs were very different matches, but both offered plenty of tactical intrigue. Here's a key tactical talking point from each.

Barcelona 3-0 Liverpool: Left-backs make inroads

On one hand, this home win was all about Lionel Messi. But in a tactical sense, Liverpool managed to deny him space effectively: He found himself in the right position for a fortunate rebound in front of an open goal, and then curled in yet another majestic free kick.

On the other hand, the battle here was all about the left-backs. Jordi Alba has probably been Barcelona's second-best performer this season, while Liverpool's full-back pairing have recorded a steady stream of assists. With Trent Alexander-Arnold omitted and the more defensively solid Joe Gomez coming into the side on the right, this meant Andy Robertson would carry the attacking threat.

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Ernesto Valverde's decision to play Arturo Vidal might have been designed to stop Robertson. He was used instead of the more technical Arthur, which meant Ivan Rakitic played a left-centre midfield role, and Vidal played on the right of midfield, tasked with shutting down Robertson. He didn't always do this particularly effectively, however, and in the first half, Liverpool's bright moments came when Robertson overlapped aggressively. With Sadio Mane's speed worrying Sergi Roberto, Liverpool looked dangerous down that side.

Jurgen Klopp made no such attempts to contain Alba, aside from the concession of starting Gomez. His team selection, including a fourth midfielder because of Roberto Firmino's injury, hinted at using a defensive-minded right-sided player -- Milner, perhaps -- to track Alba. Instead, Milner played as a right-centre midfielder, and Alba was often unmarked, with Mohamed Salah staying higher up the pitch.

Alba's trademark assist is getting to the byline and cutting the ball back for his pal Messi, and on 13 minutes, they nearly combined in typical fashion. It took a superb challenge from Robertson, covering expertly and matching Messi's run, to stop them.

But Alba remained the key player. On 24 minutes, he nutmegged substitute Jordan Henderson, played the ball inside to Messi and sprinted in behind for the return pass -- the type of run he has been making for several years, most memorably for Spain's second goal in the 4-0 Euro 2012 final win over Italy, when he did something identical to this with Xavi before finishing smartly. This time, however, Joel Matip read the danger and intercepted. The ball ended up out wide with Salah, and Alba sprinted back across to dispossess him and concede a throw.

From the next move, Barcelona switched play to Philippe Coutinho, he laid the ball back to Alba, and the left-back produced an absolutely brilliant cross/through ball that met Luis Suarez's perfectly timed run for the Uruguayan to put Barcelona ahead.

Liverpool rallied at 1-0 down before Messi's double. But the crucial tactical change was Valverde turning to Nelson Semedo, a second right-back, midway through the second half and deploying him in tandem with Sergi Roberto to shut down Liverpool's left. From then, Robertson had less opportunity to push forward, and Liverpool were far less dangerous.

Tottenham 0-1 Ajax: The Dutch defenders come out on top

The most intriguing clash in the first Champions League semifinal was the battle between the defensive trios: It was Ajax past versus Ajax present.

Tottenham's trio of Toby Alderweireld, Davinson Sanchez and Jan Vertonghen received their defensive tutoring in Amsterdam, while Ajax's current triumvirate is Matthijs de Ligt, Daley Blind and Frenkie de Jong. From the outset, it was the current Ajax generation who came out on top .

Fittingly, considering the Dutch interpretation of defensive play, the superiority of the Ajax trio wasn't really about defending. It was more about their ball-playing ability. Ajax silenced the crowd by keeping possession expertly, and a crucial factor was the ability of the centre-backs, in particular Blind, to fire line-breaking passes into the feet of midfielders and attackers. One early pass into De Jong bypassed Spurs' press easily, while another similar ball toward Dusan Tadic cut through both sides' entire midfields. For the first five minutes, the atmosphere at Spurs' new ground was hugely impressive. Quickly, however, Ajax silenced the home support.

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De Ligt was capable of something similar, and he emerged victorious from his physical confrontation with Fernando Llorente. It's rare to see any young centre-back so commanding in the air, let alone a centre-back who is so technically gifted and still only 19.

But the real star was De Jong, who played as Ajax's deepest midfielder but often dropped back into the defence to help Ajax play out from the back, turning their 4-3-3 into a 3-4-3. His calmness with the ball at his feet is remarkable, and he exudes a physical presence with his body positioning, belying his slenderness and relatively short stature.

Without the ball, De Jong was often performing two roles simultaneously. His primary responsibility was watching the runs of Dele Alli, who endured a quiet game. But De Jong was also always checking over his shoulder, assessing the positioning of Llorente and covering the passing lanes so Spurs couldn't hit balls into the feet of the Spaniard. De Jong was helping to nullify two of Spurs' three primary attacking threats, demonstrating tremendous tactical intelligence. It's also notable how often De Jong finds himself in position to intercept cut-backs from the byline.

Spurs' defenders were solid enough, though Vertonghen was forced off toward the end of the first half after he suffered a nasty blow to his head. That forced Spurs to reorganise and use a diamond midfield, which prompted an improvement, as the energy of substitute Moussa Sissoko helped them compete in the centre of the pitch and carry the ball forward toward goal more directly.

But Spurs struggled to create clear-cut chances, and even when they mounted spells of pressure in the second half, they found that Ajax's defenders were capable of doing the ugly stuff too. Alderweireld and Vertonghen had a great partnership together in Amsterdam and have reprised it in the colours of both Belgium and Spurs. Nevertheless, with De Ligt and Blind plus De Jong dropping back between them, this is a superior central defensive base.