Rafael Nadal overcame fellow Spaniard Carlos Alcaraz in just over three hours to reach the final at Indian Wells, where he will face Taylor Fritz.
Spain’s Nadal beat the talented 18-year-old 6-4 4-6 6-3 in a match hampered by strong winds.
It is fourth seed Nadal’s 20th consecutive victory as he continues his remarkable unbeaten start to the year.
Home favourite Fritz secured his place in Sunday’s final with a 7-5 6-4 win over Russian Andrey Rublev.
Nadal won the Australian Open in January as well as lifting the title in the warm-up event at Melbourne, then the Mexican Open a month later.
He was tested all the way by Alcaraz – who is seen as one of the most exciting prospects in tennis – in a three hour 13 minute encounter.
However, heavy winds disrupted the second set, with the chair umpire asking spectators to hold on to their possessions after items blew on to court.
Despite the wind, Alcaraz broke Nadal in a 20 minute game to eventually force a decider.
The 21-time Grand Slam champion then found the decisive break before serving the match out to reach his fourth final of the season.
“In the second the conditions became crazy,” Nadal said.
“It’s not fun playing in wind like this, it is sometimes a challenge and I can enjoy that.”
Earlier, world number 20 Fritz ended Rublev’s 13-match winning streak to reach the final.
“It sounds like a dream come true. I can’t even believe it’s real,” world number 20 Fritz told Amazon Prime.
“[It was] definitely the best I’ve played this week. I was finally putting it together, being way more aggressive than I’ve been all week.”
Fritz, 24, also revealed he suffered an ankle injury in the final stages of the match.
“I pinched the back of my right ankle,” he said. “I think it was on one of those points where I was trying to grind out balls on my serve.
“It didn’t feel too bad but the first point when I took a really explosive push-off step to return the serve, it hurt a lot.
“Hopefully, it’s just a little tweak and we’ll get it sorted out. I was looking for the trainer.”
Fritz will be aiming to become the first American men’s winner at Indian Wells since Andre Agassi in 2001