Maria Sharapova retires from Pacific Open

Maria Sharapova has been forced to retire from the Pacific Open in Tokyo due to injury.

The Russian twisted her left ankle during her quarter-final meeting with Petra Kvitova. The second seed was trailing 4-3 when she sustained the injury and retired after speaking to her trainer.

"I hit a serve and then landed awkwardly on my left ankle," she said after the match. "I felt a sharp pain and next thing I knew I was on the floor. It swelled up immediately and I knew there was no way I could continue."

Kvitova progresses to face Vera Zvonareva in Friday's semi-finals. The winner of the match will go to play either Victoria Azarenka or Agnieszka Radwanska.