Key Biscayne, April 2:

World number one Roger Federer rolled over unseeded Jose Acasuso 7-6 (7/5), 6-2 in a fourth-round match at the Sony Ericsson Open on Tuesday.

The top seeded Swiss star has not gone this deep into a season without winning a championship since 2000 — the last year he failed to win a title. Second seed Rafael Nadal also reached the quarter-finals beating Frenchman Paul-Henri Mathieu 6-4, 6-4. Like Federer, Nadal has yet to win on tour this season.

Ninth-seeded American James Blake is through to the quarter-finals after claiming a 6-3, 6-4 win over No 27 Radek Stepanek. Roddick will join his compatriot in the last eight. Roddick struggled in the first set before rallying to beat unseeded Frenchman Julien Benneteau 4-6, 6-3, 6-2. Russia’s Dmitry Tursunov failed to move through as 10th-seeded Czech Tomas Berdych claimed a 6-2, 6-2 win in their fourth-round match.

On the women’s side of the draw, Svetlana Kuznetsova spoiled the prospect of an all-Williams semi-final. Hours after Serena Williams was victorious in her quarter-final, Kuznetsova defeated Venus Williams 6-4, 6-4.

Younger sister Serena had held up her end of the bargain earlier with a 6-2, 6-0 victory over top seed and world No 1 Justine Henin. Henin had won three straight in the series against Serena — claiming quarter-final victories at Roland Garros, Wimbledon and the US Open — but was outplayed by the American.

It was another tough loss for the Belgian, who was playing her first tournament since being upset by Francesca Schiavone in the quarter-finals at Dubai.