Rafael Nadal enjoyed his first-ever win over American James Blake as he reached the last four of the Pacific Life Open.
Nadal went into the match with a 0-3 record against Blake
The Spaniard finally got the upper hand when he broke in game eight of the third set and came through 7-5 3-6 6-3.
He will face Novak Djokovic, who beat Stanislas Wawrinka 7-6 (7-2) 6-2.
In the women's event, top seed Ana Ivanovic will face fellow Serb Jelena Jankovic in the last four.
Ivanovic had a comfortable 6-1 6-4 win over Russia's Vera Zvonareva in just over an hour.
It's normal to have some difficult stages in a tournament
And Jankovic reached the semis when Lindsay Davenport retired with a back injury after losing the first set 6-2.
Ivanovic is seeking her first title since Luxembourg last September.
"I started really well," she said. "I thought I played some of my best tennis here so I was really happy about that.
"In the second set, I had a break up and then lost a little bit of concentration. I started to get a bit emotional and tried to go for too much. I lost my rhythm a little bit.
"I was just happy that at the end of the second set, I managed to keep calm and play good," added the Serb, who hit 18 winners in the match to Zvonareva's 10.
Australian Open champion Maria Sharapova, the fourth seed, and second seed Svetlana Kuznetsova will meet in the other semi-final.
Defending champion Nadal had lost all three of his previous matches against Blake and was pushed hard again, recovering from 4-1 down to win the first set.
"The thing is not beating James, the thing is being in the semi-final and beating two big players like (Jo-Wilfried)Tsonga and Blake," said Nadal.
"For me, those were two very important matches. At this moment I feel like I'm playing good tennis.
"I feel very good on the ball with my forehand so I think, if I am to win this match, I have to win with my forehand."
Djokovic had trouble in the early stages against Wawrinka and squandered a 5-3 lead in the opening set before winning the tie-break.
"I didn't play so well in the first set," said Djokovic.
"I made a lot of unforced errors. He knows that I'm going to try to be aggressive so he was waiting for his chance. He was playing very wisely.
"You can't always play on your top level and it's normal to have some difficult stages in a tournament.
"I'm happy to win such a difficult match."
The other half of the draw will see Roger Federer take on Tommy Haas and David Nalbandian face Mardy Fish on Friday.