MIAMI, March 27 (UPI) -- Serena Williams remained undefeated this year and advanced to the final of the Nasdaq-100 Open Thursday with a straight-sets victory over third-seeded Kim Clijsters before rain halted play.
Despite committing 37 unforced errors, the top seed rolled past Clijsters, 6-4, 6-2, and will defend her title against No. 6 Jennifer Capriati or Chanda Rubin.
The all-American semifinal was postponed to Friday due to heavy rain.
Williams split the first eight games before reeling off six in a row to take control. The American has won seven of eight meetings with Clijsters.
"I'm not too happy with the way I played," said Williams, who improved to 16-0 this year. "My serve wasn't there at all. But if I'm playing my best tennis, I don't think anyone right now can beat me."
Clijsters committed 28 unforced errors against just six winners, losing her serve five times.
"I felt physically and mentally empty," said the 19-year-old Belgian, who has played 29 matches this year. "I couldn't bring myself back to the level necessary to compete. I'm taking four or five weeks off after here."
Clijsters has been the last player to defeat Williams, winning the final last November at the season-ending WTA Championships in Los Angeles.
Capriati is trying to make the final of this event for the third consecutive year. She was a runner-up the past two years to Venus and Serena Williams, respectively.
On the men's side, one of two remaining quarterfinals got under way but also was postponed.
Ninth seed Albert Costa of Spain saved two match points against No. 4 Roger Federer of Switzerland and had a 6-5 lead in the decisive set when play was halted. After dropping the opening set, 6-7 (4-7), Costa bounced back in the second, 6-4.
Federer has been the hottest player on the ATP Tour the past month, winning an indoor title at Marseille and on a hardcourt in Dubai. He leads the ATP with 24 match wins and is trying to improve to 3-0 lifetime against Costa.
In the other quarterfinal, second-seeded American Andre Agassi will take on Younes El Aynaoui of Morocco.
Agassi has won 15 consecutive matches in this tournament, last losing in the 2000 semifinals to Brazilian Gustavo Kuerten. Agassi won 23 of 26 sets in that span but dropped one to Federer in last year's final.
El Aynaoui, who reached the Australian Open quarterfinals, has lost all three matches with Agassi, most recently last year in Cincinnati.
