Former world number ones Carlos Alcaraz and Daniil Medvedev will battle for a first Indian Wells ATP Masters 1000 title after straight sets semi-final victories on Saturday.

Spain's second-ranked Alcaraz, the top seed who can return to the summit with a third Masters 1000 title on Sunday, defeated 13th-ranked Italian Jannik Sinner 7-6 (7/4), 6-3 to reach his third final of 2023.

After a season start delayed by injury, Alcaraz has won the title in Buenos Aires and reached the final in Rio de Janeiro last month.

Meanwhile, Medvedev is riding a 19-match ATP win streak and seeking his fourth title in as many tournaments after victories in Rotterdam, Doha and Dubai.

The sixth-ranked Russian - who had never made it past the fourth round at Indian Wells -- survived a late surge from Frances Tiafoe for a 7-5, 7-6 (7/4) victory over the 16th-ranked American.

In control for most of the match, Medvedev needed eight match points to finally put it away with an ace on his final opportunity.

"I'm just really happy that I managed not to lose this match and not to have regrets, nightmares, whatever," Medvedev said.

Alcaraz, who beat Sinner in an epic five-setter on the way to the US Open title last year, had gained the upper hand on the Italian with an early first-set break, but he gave it back with a sloppy game that featured four unforced errors and allowed Sinner to level the set at 4-4.

With Alcaraz suddenly struggling, Sinner held for 5-4 and piled on the pressure with a set point at 6-5 that Alcaraz saved with a with a drop shot followed by a textbook volley winner.

A reinvigorated Alcaraz powered through the tiebreaker, sealing the set with a backhand cross court winner, and broke Sinner in the second game of the second set -- sealing the break with a dazzling lob.

Up 4-2, Alcaraz got out of a 0-30 jam with the aid of three straight unreturnable serves, and he closed it out with a confident game that he opened with an ace and finished with a thundering forehand winner.

"Playing against Jannik is never easy," Alcaraz said. "I knew that I had to increase my level. It was really close the first set.

"On the second I calm down the nerves, played more relaxed and (that) was the key of everything."

Alcaraz was looking forward to taking on red-hot Medvedev.

"I am an ambitious guy," he said. "I want to play against the best players in the world and I would say that Daniil is the best player right now.

"Amazing winning streak -- it's going to be a difficult challenge but I am prepared for that."

- Crazy end -

A dialed-in Medvedev had looked in control for most of the match, showing no sign of trouble from the right ankle he twisted in a fourth-round win over Alexander Zverev.

Tiafoe had reached his first Masters 1000 semi-final without dropping a set, but Medvedev kept him at bay in the opening set, winning 24 of his 27 service points.

Unable to convert three break points in the fifth game, Medvedev broke through suddenly in the 11th, another backhand into the net from Tiafoe giving him a chance that Medvedev converted with a net-skimming forehand.

Medvedev quickly gained the edge in the second, breaking Tiafoe in the opening game with a forehand winner that curled back inside the sideline as it dropped.

Up 5-3, Medvedev had three chances to claim the match on Tiafoe's serve in the ninth game, and after failing to convert, he was broken for the first time in a sloppy service game featuring three unforced errors -- including a double fault on break point.

Undeterred, he broke Tiafoe to love in the next game, but once again the American refused to yield, surviving four more match points on the way to a service break to force the tiebreaker.

"It was crazy at the end," Medvedev said. "I got super tight. I would say that (after) 6-5, 40-0, I think I got tight at deuce when I was like, 'Oh my God, that's a lot of opportunities missed. This could go not well for me.'"