Britain's Kyle Edmund says he must improve his fitness after squandering a two-set lead to lose to Fernando Verdasco in the Wimbledon second round.

The British number one was three games from victory before a slip and fatigue derailed him in a 4-6 4-6 7-6 (7-3) 6-3 6-4 loss.

British women's number two Heather Watson was also knocked out after being outclassed by Anett Kontaveit 7-5 6-1.

Five other Britons will seek to reach the third round on Thursday.

Cameron Norrie, Dan Evans and Jay Clarke are still in the men's draw, while British number one Johanna Konta and Harriet Dart are the remaining home hopes in the women's singles draw.

"It was a long match, quite a physical match," Edmund, 24, said. "The sort of physical intensity that I showed in the first part of the match gradually just declined. I was not able to keep that level up.

"I should have probably finished the match in the first place in the first part of the match, having obviously a two-sets-to-love lead and a break."

Edmund unravels after slip

Edmund, who reached a first Tour-level grass-court semi-final at Eastbourne last week and said he believed he could win Wimbledon, began confidently against 35-year-old former world number seven Verdasco.

After pushing the Spaniard hard on his serve before getting the break in the 10th game of the opening set, he was handed the second set in bizarre fashion when Verdasco decided not to chase after a lob he thought was going wide.

The ball bounced in and Edmund's roar was repeated by a packed Centre Court crowd.

But that was just about the last bit of luck Edmund had, squandering an early break to find himself taken into a third-set tie-break.

A slip towards the end of the third set left him walking gingerly and he called on the physio for treatment on his right leg and back after the tie-break.

"When you slip, it's just a bit of a shock," Edmund said.

"It didn't hold me back at all. I physically was not able to keep going with, like, the power and reaction and stuff."

Edmund, who withdrew from his second-round match at the French Open in May with a left knee problem, was once again let down by his body.

His movement became laboured and his shoulders dropped as the momentum swung in the favour of Verdasco, who wrapped up victory on the first of three match points.

'I've got to put some more hours in'

Edmund says he will work on improving his strength so that he can deal better with longer matches.

His season has been disrupted by the left knee problem that cut short his 2018 season but he said he did not want to use that as an excuse.

"Now I've got to try and put some more hours in. We talk about [matches lasting] three and a half, four hours, getting to that level. I've got to do that," he said.

"I've got to be able to play at the intensity I started the match for longer. These are not excuses. These are just stuff I've got to get a bit better at.

"I was in a position to win, and didn't."

Analysis

BBC tennis correspondent Russell Fuller

Edmund says his third set slip had absolutely no bearing on the result - admitting instead that he was just not able to maintain his physical intensity of the first couple of sets.

A lack of endurance was also an issue at last August's US Open. Regular bouts of illness had held him back, and it was hoped the removal of his tonsils had solved the problem.

But by then he had developed a knee problem which has restricted him to just 22 matches this year.

His next stop will be the gym: Edmund says he hopes to make the most of the three and a half weeks before his next tournament in Washington.

Gulf in rankings shows in Watson defeat

Estonian 20th seed Kontaveit was always going to be a difficult opponent for world number 122 Watson, who had suffered first-round exits at her previous three grass-court events.

But the Briton started well in breezy conditions, breaking in the opening game and then holding before being pegged back for 2-2. They matched each other for the rest of the set before Kontaveit stepped up a gear at 5-5.

The Estonian won the next two games to love, with Watson hitting long to hand her the first set.

From then on Kontaveit was uncompromising. She went a double break up in the second and made Watson run around the court, capitalising when the Briton's errors crept in.

"I thought today in general I was too defensive," Watson said. "I didn't use my variety enough, coming to the net.

"I'd say the first two games started well. That first set, I just felt like I had so many chances, but wasn't able to play aggressive tennis and get there. I sort of went on the back foot, just made too many errors.

"After that first set, I don't feel that I changed a lot. I just feel like she relaxed and really stepped up her level, didn't give me a look in at all."

Kontaveit, whose only WTA title was won on grass, will face Czech Karolina Muchova for a place in the third round.

Mixed fortunes for Britons in doubles

There were plenty of other Britons in action when the doubles began on Wednesday, with Cameron Norrie among those to reach the second round.

He and Spanish partner Jaume Munar beat fellow Briton Dom Inglot and American Austin Krajicek 4-6 6-3 6-4 6-7 (11-13) 6-3.

Joe Salisbury and American partner Rajeev Ram, who were runners-up to Andy Murray and Feliciano Lopez at Queen's, also progressed with a 6-3 6-4 6-2 win over Malek Jaziri and Radu Albot.

They are joined in the next round by Ken Skupski and Australian John-Patrick Smith after their 6-2 6-4 6-2 victory over the all-British pairing of Jay Clarke and James Ward.

But there were defeats for Jack Draper and Paul Jubb, Freya Christie and Katie Swan, Luke Bambridge and Jonny O'Mara, Sarah Beth Grey and Eden Silva, Harriet Dart and Katie Dunne, and Naomi Broady.