(CNN) -- Andy Roddick continued his winning run to end world No. 3 Novak Djokovic's title defense at the Indian Wells Masters Series event in California and set up a semifinal with world No. 1 Rafael Nadal.
Andy Roddick has won 11 straight matches on the ATP Tour.
Roddick's 11th straight win, coming on the back of his 27th career tournament success in Memphis last month, came easily against the out-of-sorts Serbian who committed 30 unforced errors in a 6-3 6-2 defeat.
But the American 26-year-old admitted he would face a tougher test against Nadal, who was barely stretched in a 6-2 6-4 runout against Argentina's Juan Martin del Potro.
"It's a difficult match-up for anyone," said Roddick, according to a report on the tournament's Web site. "He seems to like this surface and it probably favors him. But with the way I serve, I think I'm always in there with a shot. I'm returning better, and I'm able to mix it up with my returns."
Djokovic admitted it had been a "bad day."
"There's not much to say," he said. "He played very solid. I mean, he didn't do anything special. It was all me making incredible amount of unforced errors. I just didn't have any momentum on the court. No feel for the ball, no movement. Just no solutions."
Nadal, who is seeking to regain a title he won in 2007, hit the practice courts straight after his win over 20-year-old world No. 6 Potro in preparation for Saturday's clash with Roddick.
"I just went to serve a little bit, practice a little bit more the serve, because I served well in the beginning, but later I had some mistakes and a little bit more the backhand. I wanted to play a little bit longer the backhand. But that's it. I'm happy," the 22-year-old Spaniard said.
World No. 2 Roger Federer faces fourth-seeded Andy Murray in Saturday's other semifinal.
In the accompanying WTA tournament at Indian Wells, defending champion Ana Ivanovic of Serbia and Russia's Vera Zvonareva will contest Sunday's women's final.
Fifth seed Ivanovic defeated Russian teenager Anastasia Pavlyuchenkova 6-2 6-3, while fourth seed Zvonareva beat her doubles partner Victoria Azarenka of Belarus 6-3 6-3.