Injured Naomi Osaka retires in Australian Open third round

(UPDATED 4:07 P.M.) MELBOURNE, Australia — Two-time Australian Open champion Naomi Osaka retired with an injury during her third-round match against Belinda Bencic on Friday in Melbourne.

Osaka needed treatment on her stomach at 6-5 in a first set which she went on to lose on a tiebreak to her Swiss opponent, before shaking hands and leaving the court.

Osaka had a troubled build-up to the first Grand Slam of the year, retiring from the final in Auckland with an abdominal injury.

The Japanese star also revealed last week that she and her rapper boyfriend Cordae, the father of her daughter Shai, had split up.

But the former World No. 1 came to Melbourne in confident mood, saying that her injury was improving.

"I'm pretty optimistic about playing my match. I mean, for sure I'm going to play my match," she said before the start of the tournament.

"I've been practising pretty well for the two days that I've been here, so it seems to be going good."

Osaka, a four-time Grand Slam champion, reached the third round of a Slam for the first time since the birth of Shai with fine wins over Caroline Garcia and Karolina Muchova.

But both went to three sets at Melbourne Park and clearly had taken a toll.

Osaka led 5-2 in the first set against Bencic before becoming hampered on her serve and in her movement, allowing Tokyo Olympic champion Bencic to draw level and take it to a tie break, which she won 7-3.

Osaka could not continue and left John Cain Arena waving to fans.

"It's not the way you want this match to end. I thought it was getting to be a good match," Bencic said.

"Hopefully she will be fine soon and can play well for the rest of this year."

Bencic will face either American third seed Coco Gauff or Canada's Leylah Fernandez in the fourth round.