Garbine Muguruza’s preparations for next week’s Australian Open were thrown into disarray when the world number three pulled out of the Sydney International due to a leg injury.

Hours after battling past Kiki Bertens 6-3 7-6(6) to advance to the quarter-finals in her opening match, the 24-year-old Spanish top seed withdrew with a right thigh complaint.

“I am disappointed but I have talked to the WTA doctors and my team after the match and following their recommendation, I have to withdraw from the tournament,” Muguruza said in a statement.

“I have felt pain in my right adductor since I started practising here. Yesterday, I felt better and wanted to play. However, during the match today the pain has been there all the time but I wanted to compete.”

The Wimbledon champion accepted a wildcard into the tournament after retiring with leg cramps during her opening match at the Brisbane International last week and called for a medical timeout after just three games against Bertens.

Muguruza, however, returned to the Ken Rosewall Arena and appeared to be moving freely, initially allaying fears of another injury setback by overcoming a woman who had beaten her in straight sets in their three previous meetings.

“Since the start I felt a little bit my adductor,” Muguruza said after registering her first win of the season. “I already felt it in Brisbane, so I thought I was going to be much better, but it came back.

“You always have to adapt… Sometimes you don’t need to have a pain. You just want to play a certain style of game or some tactic.

“I figured out that being a little bit more aggressive, shorter points, that might help me and might help me also for my game. So it’s like a winning situation.”

Muguruza’s withdrawal allows Daria Gavrilova a direct route to the semi-finals after the Spaniard’s scheduled last eight opponent won an all-Australian clash against Samantha Stosur 6-4 6-2.

Elsewhere, Agnieszka Radwanska, the 2013 champion and last year’s losing finalist in Sydney, kept her preparations for the year’s first grand slam on track with a 7-6(4) 6-0 win over teenage American qualifier CiCi Bellis.

“For sure in that match the first set was the key, key point in that match,” Radwanska said. “It was really tight, and a lot of good tennis in that first set. I think she was a little bit upset about losing that first set.”

The Polish 28-year-old will meet Italian qualifier Camila Giorgi for a place in the last four. Giorgi shocked two-time Wimbledon champion Petra Kvitova 7-6(7) 6-2.

Giorgi, belying her ranking of 100th in the world, beat US Open champion Sloane Stephens in the first round and added another Grand Slam champion to her list of victims in just under two hours when Kvitova blasted a forehand wide.

In the men’s draw, Italian veteran Paolo Lorenzi ousted top seed Albert Ramos-Vinolas of Spain in straight sets in the second round.

Ramos-Vinolas needed treatment for a leg problem early in the second set and fell 6-3 7-5 to the 36-year-old Lorenzi, who is ranked 45 in the world.

Sydney Women’s Singles results

Second Round

1-Garbine Muguruza (ESP) beat Kiki Bertens (NED) 6-3 7-6(6)

Daria Gavrilova (AUS) beat Samantha Stosur (AUS) 6-4 6-2

Camila Giorgi (ITA) beat Petra Kvitova (CZE) 7-6(7) 6-2

Agnieszka Radwanska (POL) beat Catherine Bellis (USA) 7-6(4) 6-0