NEW YORK (Reuters) - Naomi Osaka said a new mindset had helped her to an unbeaten record since tennis resumed after the coronavirus shutdown and she is determined to take it with her into her third Grand Slam final on Saturday.

The 22-year-old appeared unflustered throughout a high quality US Open semi-final against American Jenny Brady on Thursday and emerged a 7-6(1) 3-6 6-3 winner after a thriller on Arthur Ashe Stadium.

The 2018 US Open and 2019 Australian Open champion now gets to test her mental strength against a revitalised Victoria Azarenka, who stunned Serena Williams in Thursday's other blockbuster semi-final.

"I feel like the older you get, the more mentally strong you are," Osaka told reporters.

"I think that's something that you learn from being on the tour for such a long time, playing so many matches.

"For me, definitely my goal during these two tournaments was to be more mentally strong and to fight for every point. So that's what I'm going to go into the final with. Nothing is going to change that."

Osaka returned from the shutdown at the Western & Southern Open, winning four matches before withdrawing from the final, against Azarenka, with a hamstring injury.

"I tried as hard as I could during the quarantine to get myself ready," she added. "For me, I felt that's the only thing I could possibly do.

"My first match (back), I was super nervous. But I was really happy with the level that I was playing. I just tried to keep building from that. Now I'm here, so..."

Osaka is 2-0 in Grand Slam finals but is approaching her third with a philosophical outlook.

"Even if I do happen to, I don't want to say lose but don't achieve my goal in the final, at least I get a shiny little trophy," she laughed.

"At least I can leave with something."