Top seed Nadia Petrova made short work of China's Zheng Jie with a 6-2, 6-3 victory to move into the quarter-finals of the Amelia Island championship on Thursday.
Also advancing to the last eight were No.2 seed Jelena Jankovic with a 6-2, 6-0 win over Alona Bondarenko (16), number five seed Dinara Safina who bested Katarina Srebotnik (11) 6-3, 6-1 and number six seed Ana Ivanovic, who beat Nathalie Dechy 6-1, 6-1.
Defending champion Petrova closed out her match in style, opening the final game with three of her seven aces in the match.
She narrowly missed making it four in a row, but then claimed victory when Zheng punched a backhand into the net.
"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 meet Safina in the quarter-finals on Friday, an opponent she beat two weeks ago at the Sony Ericsson Open in Miami.
"She's a tough opponent but I've had two straight, two-set matches that I won and I'm very confident," said Petrova.
Jankovic was the quickest finisher on Thursday, taking just 27 minutes per set in her win over Bondarenko.
"I just tried to be aggressive and not to let her play her game," she said. "I wanted to have the offence, the initiative in the match and that's what I did.
"I'm still trying to get adjusted to the clay courts and moving my feet. I did better today."
Jankovic will meet Ivanovic in the quarter-finals.
Also advancing were Tatiana Golovin, who posted a 6-2, 6-1 win over Samantha Stosur, and unseeded Venus Williams who beat Meilen Tu 6-2, 7-5.
