MADRID (AP) - Novak Djokovic lost 7-6 (2), 6-3 to Janko Tipsarevic in a stunning upset in the Madrid Open quarterfinals on Friday, becoming the latest big name to lose on the new blue-clay court.
Tipsarevic won for the second time in five matches against Djokovic, who last lost at this stage in November at the Paris Masters.
While Djokovic had little trouble holding serve early on, Tipsarevic had to save four break chances to force the first-set tiebreaker that he dominated.
The seventh-seeded Tipsarevic broke Djokovic to go ahead in the second set and finished off the upset after Djokovic hit two late aces to save three match points.
On the women's side, Serena Williams cruised past No. 2 Maria Sharapova 6-1, 6-3 to advance to the semifinals along with top-ranked Victoria Azarenka. She rallied past French Open winner Li Na 3-6, 6-3, 6-3.
Second-ranked Rafael Nadal lost to Fernando Verdasco on Thursday. After his loss, Nadal said he wouldn't return to the tournament unless it reverts to red clay. Djokovic said he wouldn't either, describing the new surface as slippery.
Tipsarevic advanced to a semifinal with either third-seed Roger Federer or fifth-seed David Ferrer.
Also, Argentina's Juan Martin del Potro used 10 aces to beat Alexandr Dolgopolov of Ukraine 6-3, 6-4 and reach the semifinal with Tomas Berdych.
The six-seeded Berdych defeated Fernando Verdasco 6-1, 6-2. The Spaniard made 24 unforced errors and showed little of the flare on display Thursday when he ousted Nadal.
Williams opened strong, hitting six aces and earning two early breaks to take the first set.
Sharapova broke at love to even the score at 2-2 in the second set, but she quickly squandered her break with a costly sixth double-fault to fall behind for good.
Williams sealed her seventh straight win over Sharapova with an emphatic slam.
Williams, who improved to 11-0 on clay this year, will face Czech Lucie Hradecka after she upset U.S. Open champion and fifth seed Sam Stosur 7-6 (8), 7-6 (6).
Azarenka, who has won four titles this season, then used her powerful groundstrokes to take a 4-0 lead in the second set before holding off Li's late charge.
Azarenka agreed with Nadal and Djokovic in their criticism of court's new surface.
"You feel unstable sometimes, actually, a lot of times," she said. "But right now there is no point on talking about it. After the tournament all the players can get together and discuss it."
The Belarusian will face Agnieszka Radwanska, who beat American Varvara Lepchenko 6-4, 6-4.