There are five American men ranked in the ATP top 50.

But Brandon Nakashima is showing there is at least a sixth that should be getting some love. 

Nakashima pulled off the biggest upset on Day 1 of the US Open, powering to a shocking 6-2, 6-1, 6-4 victory over No. 15 Holger Rune. 

“It’s nice to see a bunch of other young guys or lower-ranked guys challenging, and pushing down to new highs,” Nakashima said of the young U.S. contingent. “I’d say that that’s what we want to be on this list of the top American players, but we’re just working hard and obviously wish all the American players the best. 

“I’m just kind of looking forward to the next match. It’s going to be another tough match whenever I play. But we’ve just got to kind of take it one match at a time and hopefully I can continue playing the level that I did today.” 

While it marks the second straight year that Rune has gone out in the first round at Flushing, it doesn’t detract from either Nakashima’s dominant outing or his impressive bounce-back summer. 

He fell from a career-best No. 43 to outside the top 150 in just six months.

But last October, Nakashima started working with a new coaching staff led by Italian Davide Sanguinetti, a former top 50 player himself who won two ATP Tour titles.

The impact has been quick and clear. 

“They gave me a lot of perspective on what every player goes through in their career,” Nakashima said. “They definitely gave me a lot of insights through the ups and downs, just to keep working hard and managing those moments, when it’s good or bad. But, yeah, they definitely helped me a lot in all aspects of my game, and also the mental part as well.” 

Nakashima now has four wins over top-25 foes this summer, also taking out Arthur Fils, Sebastian Baez, and American Taylor Fritz.

He had just four ATP top 20 wins for his career coming into this season. 

“Yeah, they definitely helped me a lot with that confidence, whether it’s off the court or in practices, just kind of getting that confidence back,” Nakashima said. 

“At the beginning of the year their advice was to plan the schedule where I played a few challenges in the beginning of the year, got a lot of wins under my belt. And even if it was at the lower level and just kind of getting those wins and rising the ranking a little bit, and then once I got back into ATP tournaments, it’s just a matter of just kind of staying consistent with my game.”