Holger Rune has not only been backed as a potential US Open winner — he's expected to compete for every Grand Slam event now.

That's according to his Danish compatriot and former Wimbledon winner Frederik Lochte Nielsen who sees the current No. 6 as a contender at Flushing Meadows later this month.

However, there is one factor that could affect the 21-year-old.

“I feel that as good as Holger is, I expect him to compete for the title every time he enters a Grand Slam,” Nielsen told SpilXperten (via Tennis 365). “He is extremely fast on the court. The tournaments in Paris and Stockholm were a bit different because they were indoors.

“New York can be extremely hot and humid. That’s not something you experience in Paris or Stockholm indoors. So, that’s something to consider as well.”

That said, Rune has all the attributes to mount a serious challenge on the hard courts in New York according to Nielsen.

“But he’s extremely fast from the baseline, which means he can withstand hard-hitters, and he’s good at moving forward and following up at the net,” he added. “He has a lot of weapons to trouble his opponents. He has really improved his serving, and he’s good at returning.

“He is a good all-round player, capable of playing on all surfaces, and he adapts well to different playing conditions.”

Rune — seen by some as a member of a potential new Big Three — is currently competing at the ongoing Canadian Open in Toronto, Canada.

While he's happy with what he's achieved in the last year, his goal remains the same — winning Grand Slam titles and eventually becoming World No. 1.

“I improved a lot, both mentally, physically. I really took everything much more serious I would say and I was really determined to push every single day, every tournament I played,” Rune told ATPTour.com. “I feel like after the [2022] US Open swing, I really worked even harder and I got to the level where I wanted to be. I thought I was working hard, but then my results weren’t there, and then I worked 10 times harder. I think it’s always been like that.

“When I want something, I’m willing to do whatever it takes. And last year, I was not satisfied with where I was at that moment. And I thought, ‘Okay, there’s one way and it’s to put your foot down and just work’. I’m happy to be No. 6, but I’m not satisfied. And I don’t want to end at No. 6. I want to be No. 1, it’s no secret. Right now I’m also trying to work 10 times harder than I did in the beginning of the year. So hopefully, everything will come together.”