KEY BISCAYNE, Fla. — Defending champion Serena Williams and top-ranked Justine Henin had straight-sets wins today in the second round of the Sony Ericsson Open.

Williams, a four-time tournament champion, won 6-1, 6-2 over Edina Gallovits for her ninth win in 10 matches this year. The 26-year-old Williams lives nearby in Palm Beach Gardens.

Henin defeated Angelique Kerber 6-4, 6-2, showing no signs of the knee injury that troubled her at the start of the year. The top-seeded Belgian hit 40 winners to only eight for her 80th-ranked opponent in raising her record this year to 13-2.

Henin, runner-up to Williams at Key Biscayne last year, is looking to win this event for the first time. She has won two titles in 2008, in Sydney and Antwerp.

Henin said this week she began the year with pain in her right knee and considered surgery before deciding to treat the injury with cortisone and rest.

"I feel much better physically today than I did a few weeks ago — that's for sure," Henin said. "So we could see it in my serve. ... I can play with my forehand again, and I feel that everything is better now."