REUTERS - Roger Federer battled into the quarter-finals of the ATP event in Indian Wells on Wednesday with a 6-3 5-7 6-2 victory over Fernando Gonzalez of Chile.

The world number two raised his game when he needed to as he came through his first real test of the week, setting up a clash with 10th seed Fernando Verdasco.

Defending champion Novak Djokovic came through another tight encounter, beating Swiss Stanislas Wawrinka 7-6 7-6, while Britain's Andy Murray also advanced after opponent Tommy Robredo retired injured.

"I enjoy playing Fernando because it's so tactical," Federer said.

"But then at the same time it's so brutal, so aggressive. You think you have a slight chance to win the point, and then you realise, no, there's actually none."

Federer cruised through the first set but Gonzalez, unleashing a series of spectacular forehand winners, broke in the 12th game of the second set to force a decider.

Federer then hit another gear, breaking in the third game of the third set and then again in the seventh before serving out for victory.

The Swiss has won both his previous matches with Verdasco, but the Spaniard looked in good form in beating Philipp Kohlschreiber of Germany 6-4 3-6 6-1.

"I'm looking forward to playing more baseline rallies against Verdasco," Federer said.

"I'm sure that's going to happen. It's a good thing that I'm still in the tournament and facing an opponent who actually is going to extend the rallies a little bit. It's going to be a nice match, I'm sure."

Wawrinka had a set-point in the second set that would have taken his match to a decider, but third seed Djokovic saved it and now plays either Andy Roddick or David Ferrer.

Fourth seed Murray cruised into the last eight when Robredo retired with a right wrist injury. The Scot was leading 6-2 3-0 when Robredo quit.

Murray will meet Croat Ivan Ljubicic, who saved five match points before beating Russian Igor Andreev.

Later on Wednesday, world number one Rafa Nadal plays Argentine David Nalbandian.

Beaten Safina puts number one spot to back of her mind

Becoming world number one was secondary to regaining her aggressive nature on court, Russia's Dinara Safina said after she was knocked out of the WTA event in Indian Wells on Wednesday.

The Russian would have overtaken Serena Williams at the top of the rankings had she reached the final, but instead was beaten 6-7 6-1 6-3 by eighth seed Victoria Azarenka of Belarus in the quarter-finals.

"I'm not thinking about this because if it comes, it comes," she said of the top ranking. "If I play like this, definitely it will not come."

She has climbed the rankings in the past year on the back of an aggressive all-round game but said she had got away from that in recent weeks.

"I played three rounds before and I was struggling with every player that I'm playing," she said.

"With everyone I played, they were either serving for the set, or had set points. I have to finally start playing my game, because I'm not playing it.

"I just want for the next tournament (in Miami next week) to finally play my game and play like I've been playing like last year.

"Since Australia, I'm playing defensive, and it's not me. I just want to play aggressive."