Injured Muguruza withdraws from Sydney tournament

Spain's world No. 3 Garbine Muguruza was forced to pull out of the Sydney International with an injury, just hours after her win over Kiki Bertens yesterday.

A week after retiring from the Brisbane International with cramps, leading Australian Open contender Muguruza had an early medical time-out for a thigh injury before beating Bertens 6-3, 7-6 (8/6).

But the win came at a cost.

The Wimbledon champion later announced that she would be pulling out of the tournament, handing Australian Daria Gavrilova direct passage to the semi-finals.

Muguruza's decision comes less than a week before the Australian Open in Melbourne.

"I am disappointed, but I have spoken to the WTA doctors and my team after the match today and, following their recommendation, I have to withdraw from the tournament," she said.

"I have felt pain in my right adductor since I started practising here. Yesterday, I felt better. However, during the match today, the pain was there all the time, but I wanted to compete."

Muguruza was leading 2-1 in the opening set when she sought a medical time-out. She showed few ill-effects upon her return to the court, reeling off six of the next eight games to take a commanding lead.

The Spanish top seed claimed the first set before needing a tiebreaker to see off her opponent.

Gavrilova downed Samantha Stosur in their all-Australian second-round night match 6-4, 6-2.

Meanwhile, Poland's Agnieszka Radwanska reached her fifth Sydney quarter-final with a straight-set win over American qualifier Catherine Bellis 7-6 (7/4), 6-0.

Radwanska will play Italian qualifier Camila Giorgi, who eliminated two-time Wimbledon champion Petra Kvitova 7-6 (9/7), 6-2.

In the men's event, Italy's Paolo Lorenzi won 6-3, 7-5 against Spanish top seed Albert Ramos-Vinolas, who needed treatment for a leg problem early in the second set.

Lorenzi will meet Russian qualifier Daniil Medvedev in the quarter-finals. - AFP