INDIAN WELLS: Serena Williams withdrew before her semifinal at the BNP Paribas Open on Friday night with a sprained right knee, 14 years after her sister Venus did the same thing and triggered an angry reaction from fans that drove Serena to boycott the tournament.
The world's top-ranked player was to play third-seeded Simona Halep in the second semifinal. Serena addressed the crowd on-court after Jelena Jankovic defeated Sabine Lisicki 3-6, 6-3, 6-1 to reach the final.
"A couple days ago at practice I really injured my knee," Williams told fans. "Today I was struggling just to even walk."
After Serena's brief comments in which she didn't clarify she had withdrawn, fans applauded with only a few boos. As she walked off, the announcer said she wouldn't be playing and he apologized. She played four matches since being warmly welcomed back a week ago Friday, winning three in straight sets.
In the men's category, Roger Federer defeated Tomas Berdych 6-4, 6-0 and Milos Raonic outlasted Rafael Nadal 4-6, 7-6 (12-10), 7-5 in a three-hour marathon to set up a semifinal showdown. Federer improved to 15-1 this year, with his only loss coming against Andreas Seppi in the third round of the Australian Open. Federer avenged that defeat in the same round at Indian Wells. He earned his first straight-set win over Berdych since 2011 in Paris and just his second 6-0 set ever in 19 career matches against the Czech.
Federer needed just 68 minutes to advance to the semis against the sixth-seeded Raonic. Top-ranked Novak Djokovic takes on fourth-seeded Andy Murray in the other men's semifinal Saturday.
Federer had 21 winners, equaling the number of unforced errors by Berdych. Federer won 13 of 14 points at the net, never faced a break point on his serve, and broke Berdych four times in the match, including three times in the second set.
Raonic beat three-time Indian Wells champion Nadal for the first time in six career meetings, firing 18 aces and hitting 48 winners to 25 winners for Nadal, who had 22 unforced errors.
"It's really great what I was able to do today and I'm very happy with it, but I don't let myself get caught up because this isn't where it ends," Raonic said. "There is a lot more that I want to achieve this week."