Defending champion Agnieszka Radwanska led a parade of top seeds into the Dubai Championships quarter-finals on Wednesday, although her victory was overshadowed by the abrupt withdrawal of Serena Williams with a back injury.
Williams, who became the oldest top-ranked woman on Monday, said she has had a sore back and ankle since the Australian Open, though she still reached Sunday’s final in Doha.
Her departure, announced 45 minutes before she was due to face 11th-ranked Marion Bartoli, came a day after second-ranked Victoria Azarenka, who beat Williams in the Doha final, withdrew with a right foot bone bruise.
“I’ve just had some back problems the past couple weeks. It didn’t get better,” Williams said. “I thought it would get better as the week went on, but it didn’t. I don’t want to keep pushing it and make it worse.”
Former US Open champion Sam Stosur joined Radwanska in the quarters, getting the better of Taiwan’s Hsieh Su-wei 6-4, 6-0. It was a disappointing exit for the Taiwanese No. 1 following her impressive 6-1, 6-3 first-round victory over world No. 23 Varvara Lepchenko of the US.
Bethanie Mattek-Sands of the US and Sania Mirza of India beat No. 5 seeds Hsieh and Liezel Huber of the US 6-4, 6-4 in the doubles.
In the singles, former No. 1 Caroline Wozniacki brushed aside an error-prone Zheng Jie of China 6-1, 6-0, while former Wimbledon champion Petra Kvitova beat former No. 1 Ana Ivanovic 7-5, 7-6 (7/1).
The only upset of the day came when Roberta Vinci of Italy defeated fourth-seeded Angelique Kerber 7-5, 6-1. It was the latest disappointment for the German, who crashed out of the Qatar Open in the round-of-32.
Radwanska had a tougher-than-expected test in winning 7-5, 6-3 against Yulia Putintseva of Kazakhstan, who has only beaten two top 50 players.
The fourth-ranked Radwanska was down a break in both sets, but after a five-minute rain delay in the first set, the Pole broke back to make it 4-4 and then won the set when Putintseva missed easy shots.
The 101st-ranked Putintseva broke to go up 2-1 in the second, but Radwanska broke right back and later won three straight games to finish off the match.
“Even when I didn’t play my best tennis today, I was really fighting for every point and just happy, especially about the first set, that I could come back and then win that match in two sets,” Radwanska said.
Wozniacki said her confidence was back after she was plagued by injuries and disappointment at the Grand Slams last year. It has shown in the past two weeks, where she lost a close match to Radwanska and has only lost five games this week.
“I’m making the right decisions on court in terms of where I play the ball and, you know, not force myself to do things that aren’t necessary,” said Wozniacki, who is back in the top 10. “That’s mostly it, you know, the understanding of the game and just enjoying being out there.”
Kvitova struggled for much of her match with her serve — finding the mark with only 57 percent of her first serves and committing eight double faults, one of which cost her a game when she was serving for the first set.
“It started pretty well. Then Ana tried to play quite aggressively, and then I had some trouble,” the eighth-ranked Kvitova said. “So she came back. She served quite well.”
Bartoli received a walkover and will face Wozniacki, the 2011 champion, in the quarter-finals.