KEY BISCAYNE, Fla. (AP) — Volleys came at Serena Williams in a flurry. She sprinted to her right to chase one down, then to her left, then right, then left, finally ripping a backhand winner to end the frantic exchange.

Williams always seems to rise to the challenge at the Sony Ericsson Open, where she has won four titles and is back in the quarterfinals. She beat Kaia Kanepi 6-3, 6-3 Monday and will next play top-ranked Justine Henin, renewing one of the best rivalries in tennis.

She's sure to be fired up again today when she faces Henin. Williams has lost their past three meetings, all last year, at the French Open, Wimbledon and the U.S. Open.

No. 1 Roger Federer and newly engaged Andy Roddick reached the fourth round on the men's side. But Lindsay Davenport hit a bump in her career comeback when she lost to Dinara Safina 6-3, 6-4.