Rafael Nadal took another step in his return from injury with a convincing victory over a hurting Roger Federer on Thursday in the quarter-finals of the Indian Wells Masters.

Nadal broke Federer three times in the second set en route to a 6-4, 6-2 victory over the 17-time Grand Slam champion, who has been nursing a nagging back injury.

"I don't think Roger was 100 percent tonight," said Nadal, who nevertheless said the win over his great rival was a key step in his comeback from a seven-month absence rehabilitating his damaged left knee.

"I'm very happy to be in the semi-finals," Nadal said. "It was an important win for me -- they all are now."

Nadal, the former world No. 1 and winner of 11 Grand Slam titles, returned in February and notched one runner-up finish and two titles in a three-tournament Latin American clay-court swing.

But Nadal hadn't tested his knee on hard courts since pulling out of the Miami Masters last March.

Nadal improved to 19-10 against Federer in a rivalry stretching back to 2004 and including some epic clashes on the game's biggest stages.

But they hadn't met since their semi-final meeting here last year, which Federer won en route to his fourth Indian Wells crown.

Nadal didn't face a break point in the opening set, kept the pressure on Federer's serve and earned the only break he needed in the seventh game for a 4-3 lead.

He secured the set with a service winner on his fourth set point.

Nadal, making effective use of his forehand, sped to a 3-0 lead with two breaks of serve in the second set.

Federer regained a break in the fourth game -- his first break chance of the match -- but an uncharacteristic number of errors kept him from making any more inroads and Nadal wrapped up the victory after one hours and 24 minutes when Federer netted a backhand.

"It's obviously a small issue," Federer said of the back trouble that he has received treatment for throughout the tournament. "That doesn't work against a guy like Rafa.

"At least I could serve full, and that always gives you a direction," added Federer, who said he didn't want to harp on his injury and take away from Nadal's performance.

Federer now heads into a break of several weeks. He had already said he wouldn't play the Miami Masters starting next week and currently plans to return at Madrid in May.

Nadal advanced to a semi-final showdown with sixth-seeded Czech Tomas Berdych, a 6-4, 6-4 winner over South African Kevin Anderson.

Berdych has reached the final four without dropping a set and said his run in the first Masters tournament of the year was a morale booster, especially coming after such impressive wins this season as a semi-final win over Federer in Dubai, where Berdych saved three match points to advance.

"It feels great," the 27-year-old said. "It's the first Masters of the year, it's very important for me for the confidence."