NEW YORK (REUTERS) - Naomi Osaka believes the pressure she has put on herself to turn around her on-court struggles in time for the US Open has left her "very anxious" heading into the year's final Grand Slam.

Osaka, who counts two New York titles among her four career Grand Slam triumphs and has been open about her mental health struggles, revealed her feelings when asked about her mindset ahead of the Aug 29-Sept 11 US Open.

"I feel like I would have lied, like, a day ago or so and said that I was really relaxed. But actually, like, when I practised today I felt very anxious," Japan's Osaka told reporters on Saturday (Aug 27).

"I think it's because I really want to do well because I feel I haven't been doing well lately."

Osaka's hardcourt swing leading into the US Open has been rough as she lost in the second round in San Jose, retired from her first-round match in Toronto with a back injury and fell at the first hurdle in Cincinnati.

That trio of tournaments marked the former world number one's first events since the French Open, where she lost in the first round, as she recovered from an Achilles injury.

But Osaka hopes a return to the New York hardcourts, where she triumphed in 2018 and 2020 and last year lost to eventual finalist Leylah Fernandez, will help her to find her way.

Osaka, who has fallen to 44th in the rankings, will open her US Open campaign against 19th-seeded American Danielle Collins.

"It's tough. Like, of course, you don't want to lose in the first round of a slam. I feel like I always do pretty well here.

It's kind of, like, taking the pressure off of myself, but it's always going to be there," said Osaka.

"I think the opponent I'm going to play is also really tough, so it adds a little bit extra. I'm just trying to enjoy the time that I have here."