Naomi Osaka ended a four-match losing run in unfortunate fashion in Tokyo when Daria Saville retired injured in only the second game of their match.

The Australian’s career has been blighted by injury, including long-term knee and achilles problems, and only this year she returned to the top 100.

Saville yelled in pain after playing a short forehand and collapsed to the court in distress clutching her left knee.

She was able to walk away but did not risk continuing, shaking hands with Osaka after only 11 points.

Osaka has had her own injury problems this year with achilles and back issues and the former world No.1 had not won a match since the beginning of August.

“I feel really bad right now because of how it ended,” the Japanese player told the fans at Ariake Coliseum.

“I’ve been injured for most of the year so I just want people to clap for her because she’s a really amazing player.”

She will take on Brazilian fifth seed Beatriz Haddad Maia in the second round.

Can we all pray it’s not ACL… 😭 getting MRI tomorrow

— Daria Saville (@Daria_gav) September 20, 2022

Earlier, Australian Ellen Perez was knocked out in the opening round after battling through qualifying to compete.

The 26-year-old from City of Shellharbour won more games than Xinyu Wang, but lost 7-5 1-6 6-4.

Perez, rated 352 in the world, twice looked in control against an opponent 274 places above her in the standings, taking the opening three games, then romping the second set.

But her first serve dropped off in the third set, managing to land just 50 per cent, and her Chinese opponent took advantage.

Terrible moments for Daria Saville in the early going v Osaka. Ran around to hit a forehand and felt something in her knee. In big pain. 🙁 pic.twitter.com/s5PrESwqng

— Stephanie Myles (@OpenCourt) September 20, 2022

Seventh-seeded Karolina Pliskova also advanced after with a 6-2 6-1 win over Isabella Shinikova while China’s Zhang Shuai beat Japanese wild-card entry Mai Hontama 6-0 6-3.

Former world No.1 Pliskova, who was the champion in Tokyo four years ago, had little trouble against the inconsistent Shinikova.

The Czech player said she was back on form after injuring herself at the start of the year.

“I missed the beginning of the season because I broke my arm, so I had a slower start to the season, but I feel like in the summer in America I was playing really good matches,” Pliskova said.

“I reached the quarter-finals in the US Open and played some really good matches, so I think I’m in good shape and let’s see how far I can go this week.”

Former Australian Open champion Sofia Kenin’s struggles continued with a 7-6 (9-7) 6-4 defeat by Mexico’s Fernanda Contreras Gomez.

Elise Mertens won the first three games against Qiang Wang before Typhoon Nanmadol forced play to be suspended for 45 minutes while the roof at Ariake Coliseum was closed.

The Belgian then won the next three when they resumed in a 6-0 6-3 victory.

Her 30-year-old Chinese opponent managed to get to 3-3 in the second set but Mertens then won the last three games to advance to the second round.

She now meets Claire Liu who progressed by beating fellow American Alison Riske-Amritraj 6-2 6-3.

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