Agnieszka Radwanska beat an error-prone Ana Ivanovic 6-1, 7-6 (6) to reach the Qatar Open quarterfinals, where she was joined by Caroline Wozniacki on Thursday.
The fourth-ranked Radwanska made quick work of the former No. 1 from Serbia in the first set, breaking her four times amid windy conditions. Ivanovic didn't help her own cause, committing 21 unforced errors and only getting 63 percent of her first serves in.
Wind also played havoc in Wozniacki's 7-6 (6), 6-3 win over Mona Barthel of Germany as they struggled to hold serve.
Radwanska had a closer second set, with both players holding serve until Ivanovic broke with a forehand winner to go up 6-5 only to see the Pole break back to force the tiebreak.
Ivanovic was 2-0 in the tiebreak but couldn't hold her momentum. Radwanska put it away with a lob that Ivanovic hit into the net.
"She really start to play much better in the second set, and I think, you know, she didn't make any easy mistakes," said Radwanska, who improved her record to 15-1 this year after wins at Sydney and Auckland and reaching the quarterfinals of the Australian Open.
"I really need to just play my game. She didn't give me any free points in the second set. It was really close," she said. "But I'm very, very happy that I could close this and win in two sets, because, you know, in the third set you never know what's going to happen."
Wozniacki broke Barthel a second time and was up 5-3 before the German ran off three games to put her on the verge of winning the first set. But the Dane forced the tiebreaker and won it.
Wozniacki settled down in the second set, breaking Barthel twice to go up 5-1. Barthel won the next two games, but Wozniacki served out the match.
"I mean, it wasn't great tennis out there today. The wind was a huge factor," Wozniacki said. "The ball goes anywhere ... it was just about getting the ball in play. There was no Hawk-Eye out there, so there were quite a few very doubtful calls."