Miami  - Roger Federer stretched his run of form at the Miami Masters as he completed his 33rd victory Tuesday in his 11th straight year at the event, reaching the quarter-finals 6-3, 6-2 over Taylor Dent.

Dent, 27, spent six months in a body cast and underwent three back operations as he missed three years of ATP play due to the serious problem. The US player returned to the game at the start of 2009 with a ranking just inside the top 500 after his inactivity.

Federer had no time for sympathy against a difficult opponent, still known for his big serve.

The Swiss superstar battled past in less than 90 minutes to next face Andy Roddick after the US player defeated French ninth seed Gael Monfils 7-6 (7-2), 6-4.

Federer owns Roddick in their series, winning 16 of their 18 matches.

"It's going to be tough, but I feel like I'm playing well," Roddick said. "Roger seems to really serve well against me. Hopefully I'll be able to get a couple more looks on his serve."

Roddick upset Federer a year ago in Miami, which Federer avenged in January at the Australian Open, where he crushed the American.

Novak Djokovic and Andy Murray pounded out quick victories Tuesday to reach the last eight.

Third seed Djokovic will aim to reverse a stretch of four consecutive defeats against Frenchman Jo-Wilfried Tsonga, whom he last beat in the 2008 Australian Open final.

2007 Miami champion Djokovic controlled Czech Tomas Berdych 6-3, 6-2, while Tsonga, seeded 10th, ousted compatriot Gilles Simon 6-7 (4-7), 6-3, 6-2.

Murray, seeded fourth, mowed down Serb Viktor Troicki 6-1, 6-0 in 58 minutes in sweltering Miami as the Scot won his eighth match in his last nine in crushing style.

"It's especially nice when the weather is like this to get in relatively quickly," said the winner of two titles so far in 2009.

"I didn't make a lot of mistakes. I had a high percentage of first serves, used my slice well and just kept thinking all the way through the match. To get a break early, right from the start, set the tone for the rest of the match. He didn't really recover from that. By the end of the match, I didn't feel like he believed he could come back."

Since Djokovic and Tsonga met last year in Melbourne, Australia, Tsonga has taken revenge with ATP victories in Bangkok, Paris, Shanghai and Marseille.

"I've lost to him four times in a row, so he has a little advantage there," said the 20-7 Djokovic. "But all the matches were very close. It's going to be a challenge for me to win."

Djokovic has been struggling for confidence after failing to defend his Melbourne Grand Slam title and so far winning only the Dubai title in 2009.

His Miami victory marked his 10th at the event.

"Wins are necessary to get the confidence, and this is what I'm getting lately," Djokovic said. "Luckily for me, I'm winning more matches than I'm losing."

Women's eighth seed Svetlana Kuznetsova and Danish teenager Caroline Wozniacki struggled for nearly three hours in the heat before the Russian prevailed 6-4, 6-7 (5-7), 6-1, after saving 13 of 15 break points and taking treatment on the sidelines. (dpa)