Exclusive | Donald Young is trying to help America’s next generation avoid mistakes that derailed his career

American men’s tennis is having a moment.

But it could become something more: a movement.

So says Donald Young, who had the honor – and burden – of being called the Next Great American Star back when he was just 15 years old.

That never materialized. Now Young, who is in Tuesday’s mixed doubles semis with Taylor Townsend at the US Open, is preparing to retire from the sport 20 years later. And he sat down with The Post for a wide-ranging interview that covered his career, regrets and advice to the new generation of U.S. men.

Those American men have been on the rise, with five ranked in the Top 20 for the first time since Feb. 24, 1997: No. 12 Taylor Fritz, No. 13 Ben Shelton, No. 14 Tommy Paul, No. 16 Sebastian Korda and No. 20 Frances Tiafoe.

“I’m excited. I’m loving it,” Young, now 35 years old, told The Post. “They have each other. When you have that many guys that’re that good, they push each other. It’s a silent competition. You’re happy to see your mate do well, but you want that too, so it pushes you to work hard. It’s great. I’m really excited for them.

“I love Taylor, I love Francis, Tommy. Brandon Nakashima, you have all these guys. You’ve got Shelton. (Chris) Eubanks is doing well. So I’m really happy for these guys. And this is the time. It’s going to be open. These guys can be great forever…So this is awesome for these guys, and I’m super excited for them.”

Tiafoe and Fritz are playing in Tuesday night’s U.S. Open quarterfinals, while Paul pushed No. 1 Jannik Sinner in hard-fought loss on Monday night.

It’s rarified air that had been predicted for Young from his youth.

The kid from the South Side of Chicago became the youngest-ever, year-end No. 1 in the ITF rankings and turned pro in 2004 at 15. The next year he became the youngest year-end world No. 1 ever in the junior rankings at 16 years, 5 months.

But Young dropped his first nine matches on the ATP Tour without winning a set. Being rushed too early undercut his vast potential, reaching a career-best No. 38 in the ATP rankings despite that mistake.

“Maybe just the pressure of it, because leading up to that point, it was all really fun. I was a kid, I was winning, I loved to win, I was playing against my peers,” Young said. “Then I was jumped, put into a place where I was playing 25-year-olds, and people my (current) age. And there’s no way that – if I was looking at it in reverse – I was going to let someone 14, 15 beat me.

“Hindsight is 20-20 (but) it could’ve been done a lot different. But on the other hand, that means I was doing something exceptional at the time that people thought it was a possibility…So that’s cool that you started and (can) hopefully help some other people have a better route to go, or way to go about it.”

That’s why Young has tried to drop pearls of wisdom. He’s trained with Fritz in Los Angeles, he’s played doubles with Tiafoe and hosted him at his home. He even had Eubanks traveling with him when the latter was 15.

“I was happy to impart whatever knowledge I could. And I’m happy. I love to see (Eubanks) out here playing well and winning. I’m just as excited as he is when he does well,” said Young, who had sage advice for the next generation. “Keep your head down, keep listening to the people that’ve really got you there. There are a lot of people who want to sidetrack (you); you’ve got to stay focused with your head down. There are going to be ups and downs, you’ve got to ride the waves when you have them and just really be a professional. Because one day you’re going to wake up and you’re 30, and you’re going to have regrets if you don’t do it right.

“Do whatever you can, because at the end of the day when you stop you want to (know) ‘I tried this, I tried that, I did everything I could,’ and you can sleep at night. You know (if) you didn’t work hard; every athlete knows if he didn’t give 100 percent. That’s the main thing. And they have great people around them; and that’s why you have them, so you don’t have to hit the road bumps they did. It’s like a parent telling you don’t do this, because they’ve gone through it and don’t want you to go through it. Some people learn by consequence, and hopefully they don’t have to learn by consequence. They can take that knowledge and build on it.”

No American man has won a Slam since 2003, the year before Young turned pro. But he’s convinced this generation will change that. Maybe even in Sunday’s final.

“It’s coming soon. They’re going to break through. It’s too many of them doing well and going deep,” Young told The Post. “At some point you keep knocking on the door, it’s going to open. So, it’s coming; I don’t know when, but hopefully it’s here. But it’s coming.”