Bencic through to Australian Open last 16 after Osaka retires with injury

Melbourne: Swiss Belinda Bencic advanced to the last 16 of the Australian Open after two-time champion Naomi Osaka retired during Friday's third-round match with an abdominal strain that has affected her since the start of the season.

Bencic took the first set in a tiebreak 7-6(3) before Japan's Osaka, who had also pulled out of the Auckland final earlier this month due to an abdominal injury, withdrew from the contest.

Osaka had said the result from an MRI scan before the tournament "wasn't fantastic" but came through two rounds, beating Caroline Garcia and Karolina Muchova in three-set matches.

But the clash against Bencic proved to be a step too far for the 27-year-old who said her withdrawal seemed 'inevitable' after the strain she put on her abdomen in the earlier rounds.

"It's not fantastic and I'm feeling not great, not bad. In the middle somewhere," Osaka told reporters.

"It was a little hectic trying to manage it (during the tournament) because obviously my draw was quite tough.

"But we were also doing everything we could. I was going to therapy every day and into the night. So the days have been very long for me. Obviously after my last match it got way worse."

Bencic broke early to go 1-0 up but Osaka showed promise and quickly found her range to keep the Swiss at bay with an effective first serve and deep groundstrokes while she also held her nerve on a crucial hold to lead 5-2.

But Osaka, who won the title at Melbourne Park in 2019 and 2021, was visibly struggling and she lost her composure when she failed to serve out the set as Bencic grew in confidence with two searing returns.

Osaka then called for a physiotherapist during a changeover and although she initially soldiered on after treatment, she could not continue after the tiebreak.

"I really feel for Naomi, I saw her struggling a little bit at the end of the set and obviously it's not the way you would like this match to end," Bencic said.

"I thought it was a good match, so hopefully she'll be fine soon and she can play well for the rest of the season."

Bencic will play third seed Coco Gauff in the next round after the former US Open champion beat Leylah Fernandez in straight sets.