SYDNEY, Australia - Top seed Garbiñe Muguruza claimed her first win of the new season after battling through a tough match against Kiki Bertens, 6-3, 7-6(6) - and then withdrew from her quarterfinal at the Sydney International with a right thigh injury.

"I am disappointed but I have talked to the WTA doctors and my team after the match today and following their recommendation, I have to withdraw  from the tournament," she said in a statement. "I have felt pain in my right adductor since I started practicing 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. I want to thank the tournament and the fans in Sydney for their support."

In her press conference immediately after the match, she spoke about the pain she suffered on court, saying: "It's very difficult, that, because if you keep playing obviously it gets worse...obviously I have in mind that next week there is a Grand Slam, but I have to also think in Sydney."

Muguruza grabbed a late wildcard into the tournament after her early loss in Brisbane - she had to retire in the third set of her opening match due to a leg cramp - and she’s had to dig deep in Sydney as she continues her Australian Open preparations.

She faced off against Bertens, who has historically been a tough opponent; they’ve met three times previously and Muguruza lost all three matches in straight sets. But their most recent clash came in 2012, and since then Muguruza has won two Grand Slams and been World No.1, cementing her presence at the top of the game.

After a shaky start that saw Muguruza take a medical time out after the third game, the Spaniard came back onto the court and rocketed into high gear. She broke Bertens twice with some smart forays to the net and consolidated to a 5-1 lead, keeping her points short and sharp.

“Since the start [of the match] I felt a little bit my abductor,” Muguruza explained. “I already felt it in Brisbane, so I thought I was going to be much better but in fact came back.

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

“I figured out that having 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.”

Things started to get tricky from there; she had two set points on her own serve before Bertens broke, then Muguruza had another two chances to break back for the set but was denied as the Dutch player held on. Muguruza finally wrapped up the set on the fifth time of asking.

The second set saw Bertens fall behind an early break, leaving her to play catch up for most of the set. With Muguruza edging closer and closer to victory, Bertens finally pounced on a lackluster service game to level them up 4-4. She switched up her tactics and stretched the Spaniard side to side, finding success off the ground against Muguruza.

But as they marched into the tiebreak it was Muguruza who was quicker off the blocks, building up a 4-0 lead and keeping the distance to close out her first victory of 2018 after a hard-fought hour and 47 minutes.