Peer topples top seed Wozniacki in Dubai

However, it was a qualifier from Russia who caused the biggest upset of the day. Regina Kulikova, world number 99, shocked second seed and world number three Svetlana Kuznetsova with a brilliant 5-7 7-6 6-4 victory to enter the quarter-finals.

Kulikova will now face Poland’s Agnieszka Radwanska, world number 9, in the quarters.

Earlier on Centre Court, Radwanska defeated Italy’s Flavia Pennetta in straight sets 6-3 6-0.

Peer will face China’s Li Na in the quarter-finals. Na, who reached the Australian Open semifinal, overcame France’s Marion Bartoli in a tough three setter 3-6 7-5 6-0.

Fourth seed Victoria Azarenka of Belarus managed to survive a tough challenge from qualifier Anna-lena Groenefeld of Germany.

The world number six won in three sets 6-1 4-6 6-3.

After Wozniacki failed to hold serve at all in the first set she managed just two holds in the second, for 1-0 and 3-2.

Despite her dominance, Peer struggled to close out the win. She served for the match twice, after breaking to lead 5-4 with a smash and then again at 6-5 when she had broken with a fine crosscourt winner.

A double-fault gave Wozniacki a break point to take the set into a tiebreak but she netted her return on the next point and Peer finally ended the match on her fourth match point.

“She played well today, she really did,” Wozniacki told reporters. “She was changing the rhythm and going in and attacking the balls. I had my chances, especially in the second set, and I didn’t take them.”

Poland’s Agnieszka Radwanska took just an hour to reach the quarter-finals, defeating 10^th-seeded Italian Flavia Pennetta 6-3 6-0.

The seventh-seeded Pole was able to take almost total control as Pennetta struggled with a left hip strain.

• Tennis