World number two Rafael Nadal rallied for a three-set victory Wednesday over James Blake to book his semifinal berth at the ATP and WTA Sony Ericsson Open.

Nadal, seeded second behind world number one Roger Federer, defeated Blake 3-6, 6-3, 6-1 as he moved a step closer to his first title of2008.

It was the Spaniard's second victory over Blake in as many starts, following his quarterfinal win over the American at Indian Wells.

Prior to that, Blake had won the first three career meetings between the two.

Nadal earned the break he needed in the third game of the third set, and held on to close out the match in Ihr 55min.

Nadal said the key to his changing fortune against Blake was a more aggressive, albeit riskier, stance.

"I think just before I was run-

ning a lot, two meters behind the line," he said. "1 think right now I'm playing a little bit more aggressive. I can lose, but I think it's the only waytotry to win."

In the semifinals, Nadal will face Czech 10th seed Tomas Berdych, who eliminated Russian Igor Andreev 6-4, 6-4 in the day's other men's quarterfinal.

In women's action fourth-seeded Serbian Jelena Jankovic reached the semifinals when Russia's Elena Dementieva retired while trailing in the second-set of their quarterfinal clash.

Jankovic led 6-1, 3-1 when Dementieva, battling a back injury for which she received treatment after the first set, decided she couldn't continue because of pain in her lower back

"I think I played pretty good tennis, especially in the first set," Jankovic said. "I was really dictating the points.

" It was my game overall that was out there on the court, and I was really happy with that. Unfortunately she stopped the match in the middle of the second

set and there's nothing I could do."

Jankovic, who had saved five match points in her battling second-round victory over Sweden's Sofia Arvidsson, booked a semifinal matchup with Vera Zvonareva, who beat Russian compatriot Dinara Safina 7-5,6-4.

Jankovic's abbreviated quarterfinal echoed her experience at Indian Wells, where she reached the semifinals when American Lindsay Davenport retired from their contest with a back injury.

The Serbian will make her fourth semifinal appearance of the year but is still seeking to make her first final of2008, having lost in the final four at the Australian Open, Dubai and Indian Wells.

On Tuesday, third-seeded Russian Svetlana Kuznetsova and American Serena Williams, the eighth seed and defending champion, advanced to the semifinals.

Williams easily defeated world number one Justine Henin of Belgium, while Kuznetsova downed Venus Williams in straight sets.