Roger Federer continued his successful start at the BNP Paribas Open with a 7-6 (7/4) 6-3 victory over Ivo Karlovic.

Federer is playing in his first ATP Tour event after overcoming a nagging back problem which has kept him out since losing to world number one Rafael Nadal at the Australian Open in January.

But he showed no signs of struggling with any injury as he cruising past Karlovic in 73 minutes, a win which follows on from his straight-sets victory over Frenchman Marc Gicquel in the opening round.

Fourth seed Andy Murray continued also his comeback from illness by easing into the fourth round of the men's event at the expense of Paul-Henri Mathieu.

The 21-year-old saw off the Frenchman 6-3 6-2 in only his second singles match since withdrawing from the Dubai Open quarter-finals last month with a virus.

Murray was happy with his form and improving fitness, saying: "It was very good apart from a couple of games.

"But I'm hitting the ball well and it was much better than the first match (against Albert Montanes).

"I felt good today. Physically I need to get a better. I was breathing harder than I'd like after some of the long points. But I was happy with my movement."

Tenth seed Fernando Verdasco, playing in his first tournament since beating Murray on his way to the Australian Open semi-finals, blitzed Richard Gasquet 6-3 6-2.

The explosive Spaniard had too much power for his French opponent and rattled off five games in row to seal victory and a fourth-round meeting with Philipp Kohlschreiber.

The German today won a battle of the unseeded players with Ecuador's Nicolas Lapentti, triumphing 6-2 3-6 6-3.

Fernando Gonzalez continued his winning run against James Blake to oust the 13th seed in straight sets.

The Chilean had won their previous six meetings and Blake could do nothing to end that sequence as the 17th seed secured a 7-5 6-1 victory.

In other matches at the event Spain's Tommy Robredo saw off Marin Cilic 7-5 7-6 (7/2) to book his place in the next round, where he will face Murray.

Croatian Ivan Ljubicic earned the biggest upset of the day with a 6-3 7-6 (7/3) win over eighth-seeded Gilles Simon of France.

Ljubicic next will face number 22 Igor Andreev of Russia, who beat 11th-seeded Frenchman Jo-Wilfried Tsonga 7-5 6-4 in the day's late match.