Haas stuns Djokovic at Miami Masters

Defending champ Djokovic lost for just the second time this season, never getting to grips with Haas, who kept the Serb off his game with a solid mixture of shots on a cool southern Florida evening.

"There are days when you don't feel good on the court and this is one of those days," Djokovic said.

"All the credit to him. He was the better player. As far I am concerned it is the worst match I have played in a long time.

"I just didn't feel good on the court. The conditions were different. The balls didn't bounce at all and he used a variety of shots very well.

"I just didn't find a solution to come back into the match. I made so many unforced errors on the forehand side."

Haas, who turns 35 next week, advances to the quarter-finals, where he will face Frenchman Gilles Simon, who outlasted Djokovic's countryman Janko Tipsarevic 5-7, 6-2, 6-2.

Haas hit seven forehand winners and won 76 percent of his first-serve
points, snapping Djokovic's 14-match winning streak in Miami.

Haas easily won the first set then clinched the victory on his second match point with a forehand winner to the open court, ending the one hour, 20 minute match on centre court.

There was no such trouble though for Serena Williams, the women's number one, and British second seed Andy Murray.

Williams moved into the semi-finals by defeating Chinese fifth seed Li Na 6-3, 7-6 (7/5), while Murray downed Italian 16th seed Andreas Seppi 6-2, 6-4 at the $8.5 million hardcourt tournament.

Breaking Li three times in each set, Williams fell behind in the second set before roaring back to hold off Li, taking the last point off the Chinese's star's serve to end matters after one hour and 50 minutes.

"It's good to be able to at least come back," Williams said. "I like to believe that I try to be a solver. I just try to do things different if something is not working.

"She played such a good tie-breaker. It was important for me to win that."

Williams had three aces and six double faults to one ace and seven double faults for Li.

"I just can't hit any more double faults," Williams said. "It's embarrassing and unprofessional. I hit about 50 in one game and it was just outrageous. It was like at this point I shouldn't be a professional tennis player.

"That was my goal -- I'm not hitting any more double faults."

Williams, trying to become the first six-time winner in Miami history, will face either defending champion and fourth seed Agnieszka Radwanska of Poland or 30th-seeded Belgian Kirsten Flipkens, who meet later, in the semi-finals.

Williams won Miami titles in 2002, 2003, 2004, 2007 and 2008. The 15-time Grand Slam champion also captured last year's US Open, Wimbledon and Olympic crowns.

Scotsman Murray, the 2009 Miami winner who lost to Djokovic in last year's Miami final, needed only 86 minutes to book a date in the last eight against the winner of a later match between French sixth seed Jo-Wilfried Tsonga and Croatian ninth seed Marin Cilic.

"Today I served well," Murray said. "You know, when I was down in games I served pretty good, too.

"That can change from day to day, but I just keep working on it each day. Focusing hard on each serve specifically."

In the men's draw Spanish third seed David Ferrer advanced to the quarter-finals with a 6-4, 6-2 victory over Japan's 13th-seeded Kei Nishikori.

Ferrer won 84 percent of his first-serve points and 5-of-9 break chances to eliminate Nishikori and book a last eight-date against Austria's Jurgen Melzer, who defeated Spain's Albert Ramos 2-6, 6-3, 6-3.

French eighth seed Richard Gasquet outlasted Spanish 10th seed Nicolas Almagro 6-7 (3/7), 7-5, 7-6 (7/3) and will next face Czech fourth seed Tomas Berdych, who dispatched US 17th seed Sam Querrey 6-1, 6-1.