Naomi Osaka ends her four-match losing streak after Daria Saville retires due to nasty knee injury in Tokyo

Naomi Osaka ended a four-match losing run after her opponent Daria Saville was forced to retire in only the second game of their opening round match at the Pan Pacific Open in Tokyo.

Saville yelled “my knee!” after playing a forehand and collapsed to the ground clutching her left knee. Osaka quickly went across to the other side of the net to check on her.

The Australian, who has endured an injury-blighted career, was able to get back up onto her feet but could not continue the match.

Both players embraced each other and Osaka wished her well after the match.

“Hi Daria, it’s Naomi. I just wanted to wish you the best. I hope you are doing better,” she said.

“I just wanted to let you know you’re one of the funniest people on the tour and I still remember all the nice things that you said to me at the French (Open) this year.

“I want you to know that I am wishing you the best. I hope that it’s not a major injury at all that you will bounce back because I know that is what you are good at.”

Osaka told reporters: “I thought that she was just yelling because she thought her forehand was out, then I realised that she was yelling because she was in pain.

“Then I got really scared because I felt like as athletes we have a pretty high pain tolerance. It seemed really bad.”

Former world No.1 Osaka has struggled with Achilles and back issues this year and had not won a match since the beginning of August. Osaka is currently No. 48 in the WTA rankings.

She will take on fifth seed Beatriz Haddad Maia in the second round after the Brazilian beat Japanese wild card Yuki Naito 6-4 6-2.

Great Britain’s Emma Raducanu begins her Korea Open campaign in Seoul against Japan’s Moyuka Uchijima on Wednesday.