Alcaraz faces Medvedev for Indian Wells title after stopping Sinner
Alcaraz's 1-6, 6-3, 6-2 victory ended Sinner's 19-match winning streak, including a 16-0 start to the year, and ensures Alcaraz will remain No. 2 in the world rankings next week.
"To be able to end something like this, it's incredible for me," Spain's Alcaraz said of busting the Italian's streak.
Sunday's final against fourth-seeded Russian Medvedev is a repeat of last year's championship decider.
Medvedev also had to fight back in a 1-6, 7-6(3), 6-2 victory over 17th-ranked American Tommy Paul. In the final, he'll be out to thwart Alcaraz's bid to become the first repeat Indian Wells ATP champion since Novak Djokovic won three straight titles from 2014-2016.
Alcaraz and Sinner's semi-final was disrupted by a three-hour rain delay at 2-1 in the first set but proved worth the wait as the 20-something stars put on a show.
"Matches with Jannik are always special," Alcaraz said. "We know we have to play at our highest level to win. We have to put magic on the court, unbelievable points and for the crowd it is also wonderful."
Sinner quickly seized the initiative when play resumed, winning four straight games to pocket the first set.
He saved the only break point he faced, and gained the insurance break for a 5-1 lead, pouncing on a short ball for a stinging cross-court passing winner on break point.
Alcaraz turned it around in the second set with a savvy change of style, backing up to give himself more time on the returns and gradually working his way into the match.
He broke Sinner with a deep volley winner for a 3-1 lead and held for 4-1 in a game that had fans on their feet cheering a thrilling rally at the net.
He saved break points in the seventh and ninth games before sealing the set with a drop-shot winner.
Mentally strong
"I stayed strong mentally," Alcaraz said. "I think that's a really important part in this game.
"This kind of match, a set down playing against someone that's playing an unbelievable game - I'm really happy with the things I've done.
"I changed my style a little bit, I changed my game a little bit, and I think it worked very, very well," said Alcaraz, who is chasing his first title since winning Wimbledon last year.
Sinner's mistakes were multiplying in the third set and Alcaraz broke in the third game, delivering a high backhand volley to end another scrambling rally.
World number three Sinner, who had dived to get a ball back, came up shaking out his right arm and rubbing his elbow.
He suddenly was powerless to stop Alcaraz, who won five straight games, clinching the match with a forehand winner.
It was the second straight year that Alcaraz stopped Sinner in the Indian Wells semi-finals.
"It's for sure not the ending that I wanted, but playing against him, it's always tough," Sinner said. "I tried to play good tennis, which I have done, especially in the first set.
"Then I made a couple of mistakes. The momentum has changed. He raised his level."
Medvedev said the chilly evening conditions made it hard to find a groove in the opening set against Paul, but like Alcaraz he was able to make some adjustments.
He won the first four games of the second set but Paul attacked the net aggressively to claw back and force the tiebreaker, in which the American rolled his ankle on the sixth point.
Medvedev won the last five points of the tiebreaker to level the match and seized a 5-1 lead in the third, finally fending off a pair of break points in the final game to close it out.
The reward is a chance to avenge last year's loss to Alcaraz and claim the only one of the six hardcourt Masters 1000 titles he has yet to win.
"I know what happened last year so I'm going to try my best to try to turn this around, to play better, to play stronger, more on the lines, hit more aces, stuff like this," Medvedev said. "Hopefully I will be able to do it."
