Russian Daniil Medvedev toppled World No. 1 Jannik Sinner 6-7 (7), 6-4, 7-6 (4), 2-6, 6-3 in a grueling four-hour match Tuesday to move into the semifinals at Wimbledon.

The victory on the grass courts of London snapped Medvedev's five-match losing streak to Sinner, who was two sets down to Medvedev in the Australian Open final in January and came back to win.

Medvedev's win set up a semifinal battle with defending champion Carlos Alcaraz of Spain, the No. 3 seed, who defeated No. 12 seed Tommy Paul 5-7, 6-4, 6-2, 6-2.

Medvedev and Sinner played an epic first set, with the fifth-seeded Medvedev serving at set point in the tiebreaker, only to squander the chance. Even after Sinner cashed in on the opportunity, Medvedev stayed calm and confident, and took the second set.

Three games into the third set, down 1-2, Italy's Sinner called for a medical timeout. After medical staff checked his pulse and his oxygen level, he was taken off the court and returned about 10 minutes later.

Medvedev, in his on-court interview, said it was tough to play against an opponent who was medically compromised.

"It's actually very tough because ... one moment I could feel that he doesn't move that well so it's always tricky because you wanna play more points to make him suffer a little bit more -- in a good way -- and at the same time you know that he at one point is gonna say, 'OK, I can't run anymore so I'm gonna go full power.'

"That's what he did and he had set points to win the third set, and yeah in a way I would maybe prefer to not have this situation, but everything is well when it ends well so I'm pretty happy."

Sinner, indeed, had two set points up 6-5 in the third set, but Medvedev fended them off to move to a tiebreaker.

"I knew if I wanted to beat Jannik, it needs to be a tough match," Medvedev said. "I felt at one moment he was not feeling that good but I knew that this can get away and then he started playing better so I'm happy that I managed to still, like stay high level. It was great points, great match and I'm really happy to win and really happy with my game and looking forward to it."

He is looking forward to a second consecutive trip to the Wimbledon semifinals against Alcaraz, who beat the Russian in straight sets last year on his way to the championship.

Alcaraz was forced to come from behind after losing the first set, in which neither player was at his best. Paul hit nine winners against 15 unforced errors, while the numbers were 10 and 15, respectively, for Alcaraz.

The Spaniard picked up his play in the second set, striking five of his seven aces in that frame. By the end, Paul had 21 winners and 51 unforced errors to 36 winners and 37 unforced errors by Alcaraz.

Alcaraz also broke Paul's serve seven times combined in the first three sets.

"He has been playing great tennis on grass. He won Queen's and has been doing great stuff here at Wimbledon, beating great players," said Alcaraz of Paul after the match. "Of course today was a really difficult match for me.

"At the beginning, the first set and the beginning of the second set, it kind of felt like I was playing on clay. Big rallies, 10 to 15 shots every point. So I had to stay strong mentally when I lost the first set. It was difficult for me a little bit, but I knew it was a long journey, a long match, and I just had to stay there. I'm really happy to find the solutions and the good path."

--Field Level Media