Roger Federer overcame a couple of moments of alarm to book his place in the fourth round of the Australian Open with a 6-3 6-3 6-1 win over Xavier Malisse.

19605 - Roger Federer shrugs off wobble to beat Malisse

The defending champion looked in control after taking the opening set, but he began to get a little agitated midway through the second. He remonstrated with line judges and threw in some alarming shots. Malisse sensed a chance and claimed a break of serve with a glorious passing shot.

But just as it appeared as if the Swiss may be teetering, the 16-time major champion hit back with an immediate break and ran through five unanswered games to take the second set.

The belief was strangled out of Malisse and Federer raced through the third set, at one stage his winning run of games stretched to 10. Malisse avoided the bagel but it mattered little as the Swiss marched on.

Federer will meet Tommy Robredo in the fourth round after the Spaniard secured a four-set win over Sergiy Stakhovsky.

Novak Djokovic eased into the fourth round, as his opponent and fellow Serb Viktor Troicki was forced to retire when one set down.

Troicki entered the game with high hopes of toppling a player he knows so well, but just eight games into the match he informed the umpire that he could not continue on account of a stomach muscle injury.

Speaking after the match, Troicki that he had first noticed a strain in his second round match against Nicolas Mahut. He said: "For almost two sets I didn't serve one ace and the percentage was really low and I was glad to win that match. I was really struggling with everything, it was really tough, it was hurting me a lot and that's why I pulled out of doubles yesterday."

Up next for Djokovic is Nicolas Almagro who got the better of big-serving Croat Ivan Ljubicic 6-4 7-6(8) 6-3.

Andy Roddick bounced back from losing the first set to book his place in round four with a 2-6 7-6(2) 6-2 6-2 win over Robin Haase. The American credits the second-set tiebreak as the pivotal moment in the match, but he appeared to pump himself up when almost decapitating Haase with an errant forehand that flew within inches of his opponent's head.

"The biggest thing was that breaker," Roddick said. "He wins that, I think that was the match. He kind of blinked for a second there for the first time of the day, and I was able to kind of turn it the way I wanted it to go. I'd love to take all sorts of credit for winning that breaker, but he hit two double faults. That's about it."

Reflecting on the moment when he rifled a ball at Haase, Roddick said: "That shot? Not enough topspin. It happens. Everyone's done it."

Haase started like a train and Roddick had no answers early on. But he dug in during the second set and after scraping through the breaker, the American took control of the match from the back of the court.

Tomas Berdych was given a test by Philipp Kohlschreiber in round two and the workout looks like it sharpened up the Czech as he found his stride to defeat classy but inconsistent Frenchman Richard Gasquet 6-2 7-6(3) 6-2.