Amelia Island, April 6:

Former champions Nadia Petrova and Venus Williams earned straight-sets wins to reach the Bausch & Lomb Championships quarter-finals on Thursday.

Top-seeded Petrova, last year’s winner, beating Zheng Jie of China 6-2, 6-3 in the third round with seven aces, including three straight in the final game. She narrowly missed making it four in a row, the ball landing just long.

“I was hoping to make it four straight in that game,” she said. “My service is a weapon that I can win a lot of points with. When you ace somebody it just feels great.” Petrova will face Russian countrywoman and fifth-seeded Dinara Safina, who defeated Katarina Srebotnik of Slovenia 6-3, 6-1. Petrova has already beaten Safina twice this year in Paris and Key Biscayne.

Williams, the unseeded 2002 champion, broke fellow American Meilen Tu in the last game to avoid a tiebreaker and win 6-2, 7-5. Williams lined up a quarter-final with eighth-seeded Tatiana Golovin, who routed Samantha Stosur of Australia 6-2, 6-1.

Second-seeded Jelena Jankovic and sixth-seeded Ana Ivanovic set up an all-Serb clash. Ivanovic, younger by three years at 19, leads their head-to-head 3-1. Jankovic beat Alona Bondarenko of Ukraine 6-2, 6-0, winning the last 10 games. “I just tried to be aggressive and not let her play her game, Jankovic said. “I wanted to have the offense, the initiative in the match and that’s what I did.” Ivanovic dispatched Nathalie Dechy of France 6-1, 6-1.

Third-seeded Daniela Hantuchova downed 17-year-old wild card Dominika Cibulkova 6-1, 6-4 in the second match between the Slovaks this year. Hantuchova’s opponent next will be Austria’s Sybille Bammer, who topped Croatian qualifier Karolina Sprem 6-2, 6-3.