MIAMI, April 1 (UPI) -- World No. 1 Roger Federer and second-ranked Rafael Nadal were straight-set fourth-round winners Tuesday at the $3.77 million Sony Ericsson Open.
Federer, a two-time Miami champion, defeated Argentine Jose Acasuso 7-6 (7-5), 6-2. Federer, the reigning Wimbledon and U.S. Open champion, is still seeking his first trip to a final in 2008.
Nadal, the reigning French Open champion and Wimbledon runner-up, beat Frenchman Paul-Henri Mathieu 6-4, 6-4. Up next for the 2005 Miami runner-up will be American favorite James Blake, who got into the quarterfinals by beating Czech Radek Stepanek 6-3, 6-4.
Czech Tomas Berdych defeated Russian Dmitry Tursunov 6-2, 6-2 to set up a round-of-eight bout with Russian Igor Andreev, who beat Argentine Guillermo Canas 6-4, 7-6 (8-6). Canas was last year's Miami runner-up to Serbian Novak Djokovic.
Also, Serbian Janko Tipsarevic defeated Russian Mikhail Youzhny 3-6, 6-0, 6-3.
The 2008 Miami champion will win $590,000.
