Belinda Bencic's previous experience as a top-10 player gave her belief she could ascend the rankings of the sport again after seeing her career derailed by injury.

Bencic reached the last eight of the US Open on Monday as he produced a magnificent display to beat defending champion Naomi Osaka 7-5 6-4.

The Swiss was ranked seventh in the world in 2016, but a succession of injury problems saw her drop to 312th by the time she returned in September 2017.

However, Bencic has worked her way back into the world's top 20 and now plays good friend Donna Vekic for a place in the semi-finals.

Asked about her experiences between her previous Flushing Meadows quarter-final in 2014 and her straight-sets defeat of Osaka, Bencic told a media conference: "Yeah, it's been a long way since then [2014], for sure.

"People always think I'm a little bit older than I actually am, because I've been here since 16, 17. I think definitely it was a good time. I learned so many things. I think everyone expected [me] to go just up. That's not how tennis goes.

"I think all true athletes have to overcome obstacles, injuries, just tough times. I think it made me a stronger person, better player.

"Of course, there were times when you're injured you wonder if you can play at this level again. Then I also believed if I'm going to get back and healthy, I can play on this level, because I proved it so many times. It was just about being consistent and if it was going to be enough.

"I think it helps when the belief is there, when you know you can be top 10. So when you have been there, you know that your way is working. So I think that helped me a lot through these injuries."

Asked about her improvement in New York, Bencic added: "I think just generally I think the mental part is just really important.

"In these top-50 players, everyone can play very good tennis, so it's not about who can hit a better backhand or who can hit a better forehand.

"I think it's definitely about the mentality, how you go to the court, how you approach, if you have fear or if you're playing freely."

In Vekic, Bencic will be playing an opponent who has endured similar struggles, having won her first WTA title at the age of 17 but then finding grand slam success difficult to come by.

"I think it means a lot, because she was also very good [at] 16, 17 won her first WTA title," Bencic said of Vekic. "Then it was, you know, the pressure and some injuries, some difficult times.

"Now we're both back. It feels very nice. I'm very happy for her. But definitely I want to win. But still I think it will be great that one of us will be in semi-final."