Key Biscayne (Florida):Rafael Nadal advanced to the fourth round of the Sony Ericsson Open by beating qualifier Frederico Gil 7-5, 6-3.
The top-ranked Nadal struggled with his second serve and was broken twice Monday but gradually wore down Gil, who is ranked a career-best 74th.
The top men have avoided the wave of upsets that has marked the women's draw. The latest surprise was 18-year-old Caroline Wozniacki's victory over fourth-seeded Elena Dementieva 7-5, 6-4.
Wozniacki, who last week was selected WTA Tour newcomer of the year for 2008, advanced to the quarterfinals. She took advantage of 45 unforced errors by Dementieva.
Wozniacki is the first Danish woman to crack the top 20, reaching a career-high 12th in the rankings while benefiting from recent workouts in Las Vegas with Andre Agassi's former trainer, Gil Reyes.
"It feels amazing to me that I'm the No. 12 in the world," Wozniacki said.
Despite a sluggish start and wobbly finish, Venus Williams defeated No. 10-seeded Agnieszka Radwanska 4-6, 6-1, 6-4. The three-time champion double-faulted three times in the last game before finishing with an ace.
"Fortunately I've had experiences like that before," Williams said. "I know how to get through it."
Williams was playing for the third day in a row, and she looked weary in the warm, sunny weather. After dropping the first set, she began to move better and won 11 of the next 13 games.
"I was hitting really well in the practice," she said. "I came out and things weren't going the way I imagined they would. But that's tennis. I feel good. I feel confident. I've been playing very well in the last few months."
Radwanska nearly overcame a 5-1 deficit in the final set, but she failed to convert three break points that would have made the score 5-all.
"Oh, that's always fun," Williams said. "Every now and then, everybody has those kinds of matches. ... I just had a lot of errors. Just errors, errors.
Williams finished with 40 unforced errors but also had 43 winners, hitting 11 aces. She's seeking her first Key Biscayne title since 2001. Her quarterfinal opponent will be No. 26-seeded Iveta Benesova, who swept No. 19 Anabel Medina Garrigues 6-4, 6-1. Williams, seeded fifth, avoided the wave of upsets that has eliminated six of the top 10 women. She and her sister, top-ranked Serena Williams, are the lone remaining players in the top seven. The sisters could renew their rivalry in the semifinals Thursday.
Two-time Grand Slam champion Amelie Mauresmo was eliminated by unseeded Samantha Stosur 6-4, 6-4. No. 8 Svetlana Kuznetsova beat Alisa Kleybanova 6-2, 6-1.