Williams sisters reach Open quarterfinals

FLUSHING MEADOWS, N.Y., Sept. 1 (UPI) -- Two-time champions Venus Williams and Serena Williams, straight-set fourth-round winners Monday at the U.S. Open tennis, will meet in the quarterfinals.

The seventh-seeded Venus beat ninth-seeded Agnieszka Radwanska of Poland 6-1, 6-3 in 1 hour, 24 minutes, with the help of five service breaks.

The former top-ranked Venus is a seven-time major titlist, including the last two Wimbledon championships. She captured the U.S. Open back-to-back in 2000 and 2001 and was the runner-up in 1997 and 2002.

Serena, the fourth-seed, defeated Frenchwoman Severine Bremond 6-2, 6-2 in just one hour. The former world No. 1 Serena owns eight major titles, including the 1999 and 2002 U.S. Open crowns. She was the 2001 runner-up to Venus and beat her older sister in the 2002 finale here.

French Open and Olympic runner-up Dinara Safina, the sixth seed, beat German Anna-Lena Groenefeld 7-5, 6-0. Safina reached the finals in six of her previous seven tournaments, including three titles.