Naomi Osaka pulls out of Italian Open quarters with hand injury

World number one Naomi Osaka pulled out of the Italian Open quarter-finals on Friday with a right thumb injury, casting doubts over her participation in this month`s French Open.

The 21-year-old Japanese was scheduled to face sixth seed Kiki Bertens after coming through two matches on Thursday in the rain-affected tournament but said she was forced to withdraw due to pain and swelling at the base of her thumb.

"I woke up this morning and couldn`t really move my thumb," Osaka told reporters. "I tried to practise and grip my racket but I couldn`t, and I kept feeling this pain when I tried to move my hand in different directions."

"Right now I`m... in between sad and disappointed because I really wanted to play my match today. For me, it was sort of a test to play against Kiki because she`s playing really well and I wanted to see how well I could do today."

"I didn`t feel anything yesterday. That`s why I`m kind of confused right now because I literally woke up in the morning and couldn`t move my thumb. So I was like, maybe I slept on it and maybe it will go away, but it didn`t."