Defending champion Carlos Alcaraz and Daniil Medvedev set up a Wimbledon semi-final repeat on Tuesday, while Daniil Medvedev defeated world number one Jannik Sinner to reach a second successive Wimbledon final four.

Alcaraz battled back from a set down to defeat Tommy Paul 5-7, 6-4, 6-2, 6-2 while Medvedev stunned world number one Jannik Sinner, who suffered a mid-match health scare, 6-7 (7/9), 6-4, 7-6 (7/4), 2-6, 6-3.

Spanish world number three Alcaraz, seeking a fourth Grand Slam title, was broken twice by 12th-seeded Paul in a 72-minute first set.

Three breaks in the third set put the Spaniard in charge and he stepped up another gear in the fourth, making just four unforced errors.

Alcaraz, seeking to become just the sixth man to capture the French Open and Wimbledon titles back to back, defeated Medvedev in straights sets in last year's Wimbledon semi-finals.

Daniil Medvedev defeated world number one Jannik Sinner in five sets on Tuesday to reach a second successive Wimbledon semi-final, subduing the gallant challenge of the Italian, who suffered a worrying mid-match health scare.

The fifth-ranked Medvedev triumphed 6-7 (7/9), 6-4, 7-6 (7/4), 2-6, 6-3 to avenge his Australian Open final loss to Sinner in January.

His four-hour victory also ended a five-match losing streak against the Italian as Medvedev reached his ninth Grand Slam semi-final.

In a tight first set in which neither man gave up a break point, Medvedev edged ahead in the tie-break on the back of a lung-busting 33-shot rally. However, he squandered a set point and his game suddenly fell apart, serving up a double fault as Sinner pocketed the opener.

The mercurial Russian carved out the only break of the second set in the third game on his way to levelling the quarter-final.

Sinner slipped another break down at 2-1 in the third set and immediately summoned the tournament physio.

The Italian, appearing distressed, had his blood pressure taken courtside before he left for a medical time-out.

After a 10-minute delay, the 22-year-old resumed play and thrilled the Centre Court crowd when he bravely clawed his way back to 5-5.

However, the Italian was undaunted and levelled the quarter-final on the back of breaks in the third and fifth games of the fourth set. But it was Medvedev finished the fresher of the two players, breaking in the final set on his way to victory. (AFP)