From California to the U.S. Open, the future of American men’s tennis tries to take over the present

Editor’s note: An original version of this story was published in January 2025.

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For a few hours on a sparkling mid-December morning in Southern California, two guys who figure to play a major role in the future of American men’s tennis beat balls across the net of a neighborhood hard court.

On the other side of a chain-link fence, a women’s pickleball foursome click-clacked through a couple of sets, seemingly clueless about the identity of the two young men readying themselves for the start of the 2026 season. The yelps and chatter of a nursery school recess clattered down from a small hill overlooking the scene.

Across the globe, other members of the ATP Tour top 40 were likely going through their paces at exclusive clubs or those vaunted academies built on Rafael Nadal’s or Patrick Mouratoglou’s name. Alex Michelsen and Learner Tien were fine to do their thing in Mission Viejo, just inland from Laguna Beach.

“I hate myself!” Michelsen screamed after a soft approach gave Tien an easy passing shot.

That brought out a little grin from the 20-year-old, who already has one of the great tennis poker faces. There were a few more grins that morning, including when Michelsen missed an easy volley.

“I should be shot!” he yelled.

Before long, they were playing a 10-point match tiebreak, with the rules according to the Next Gen ATP Finals, the tournament for the best players aged 20 and under, which Tien went on to win a week later. Michelsen aced Tien with a serve that ticked the top of the net before dribbling over. He apologized.

“We can redo it if you’re really sorry,” Tien suggested.

“I’m not that sorry,” Michelsen, 21 at the time, said. He won the tiebreak a few points later.

Within a few minutes, they were sitting on the bench beside the court, with Michelsen seeking some relationship advice from his partner in a climb to the top of their country’s tennis mountain that started in the same Orange County hills. Sometimes they were on neighboring courts at the same tennis center. More often, they shared fitness sessions on the beach.

Tennis moves fast. The current U.S. generation, led by Taylor Fritz, Frances Tiafoe and Tommy Paul, is suddenly a collection of players in their late 20s running up against time. All of them registered head-scratching losses during the season’s first week, but this U.S. Open has looked a little different.

Ambivalence has laced through Tiafoe’s relationship with tennis, though he declared himself fit for purpose at the start of the year and is back in the quarterfinals of his favorite tournament after one of the most consistent seasons of his career.

Paul was banged up for the final six months of the 2025 season. He has been mostly healthy this year but bumped into his ceiling again Sunday, losing to Carlos Alcaraz in straight sets in the fourth round.

Fritz, who has largely stood apart from his compatriots in how he has maximized his talent — regularly playing on the biggest stages against the biggest stars — hit something more like a wall. He was upset in the third round Saturday by Francisco Cerúndolo, the No. 24 seed from Argentina, who came back from two sets and a break down.

Ben Shelton, 23 and the senior in Tien and Michelsen’s cohort, is the top-ranked American man now. He and Michelsen charged into the U.S. Open quarterfinals Sunday, with wins full of flash and firepower. Tien, the No. 14 seed, has the chance to join them when he faces the unseeded, but richly experienced, Karen Khachanov in his fourth-round match Monday.

Michelsen already has plenty of big wins, a huge serve and tons of upside, according to most high-quality tennis minds. At the 2025 Australian Open, Shelton, Tien and Michelsen were three of four American men to make the second week. Paul was the other.

Seven Grand Slams later, Tiafoe has joined them in composing the tip of the spear to break the 23-year Grand Slam drought for the American men. Shelton figured to have the best shot after crushing Stefanos Tsitsipas, 6-2, 6-3, 6-4, Sunday night, but he faces a suddenly in-form Alcaraz in the quarterfinals next.

“It’s going to be fireworks Tuesday night,” Shelton said on the court after his latest win.

Michelsen has yet to lose a set in four matches. He barreled through Tomás Martín Etcheverry of Argentina on Sunday afternoon at Grandstand. He flipped the match over 4 points in the first-set tiebreak, saving a set point for Etcheverry on the Argentine’s serve by knifing a backhand volley winner. Two big serves later, he clinched the set by grinding out a 24-shot rally.

The turnaround rocked Etcheverry.

“He’s American, he’s playing here with the people — everyone supports him, of course — and he’s motivated,” Etcheverry said after the match. “He didn’t lose a set in the last four matches. He’s been unbelievable. I think he has good chances in the next round.”

Michelsen credited the fast, hot — but not too hot — conditions for some of his success this week. The heat has kept the balls lively. The slick courts then keep them low when Michelsen cracks his 130 mph serve and hard forehands and flat backhands.

“The balls and the courts here,” he said, “are just absolutely perfect — my personal opinion.”

That said, he believes he is a more complete player than he has ever been. His serve is no longer simply hard; it hits spots. And he’s no longer the “giraffe on ice” that he used to feel he resembled on a tennis court.

Still, none of this was on the cards not long ago.

“No one ever told me I would be professional until I was 16 years old,” he said during an interview Sunday. “It wasn’t talked about.”

He’s every bit of a professional now. He will face Tiafoe in the quarterfinals Tuesday at Arthur Ashe Stadium, as Tiafoe tries to keep hold of his torch.

That practice match in Orange County in December may not have featured a chunk of the future of elite American men’s tennis, but rather its present.

Michelsen and Tien have barely seen each other this U.S. Open: They are on opposite sides of the draw and playing on different days. But they are in constant contact, texting each other updates and messages of support.

“It’s always been a target in our minds that we want to catch those guys,” Tien said in December as he sat beside the court. “I’m sure, on the other hand, that they want to keep the lead on us, and they want to keep their top spots.”

It didn’t take long for the movement to appear well on its way.

A little more than halfway through January’s Australian Open, Tiafoe was out in the third round, outplayed by hometown favorite Alex de Minaur, who sent him home in three sets. Paul and a banged-up Fritz fell in the fourth round — the former to Alcaraz and the latter to Lorenzo Musetti, both younger, higher-ranked European talents who are likely to shine for the next decade or more, and one of them then the world No. 1.

Michelsen lost a tough first-round match to Khachanov, but Tien blew out Daniil Medvedev, a former world No. 1 and U.S. Open champion, to become the youngest American male to reach a Grand Slam quarterfinal in 25 years. At one point in the match against Medvedev, he won 11 consecutive games and delivered Medvedev the first 6-0 Grand Slam set of his career, in 451 sets played.

Shelton cruised to the quarterfinals before falling to Jannik Sinner.

“A lot of confidence, for sure,” Tien said after one of his wins. “I feel like I have been playing a little bit better match by match, and, you know, each match I’m making a little jump in how well I’m playing, how comfortable I feel.

“At the top of the game, all the guys play very aggressively; they all have big strengths. Obviously, it’s a goal to try and get there and compete with that.”

Seven months on from Australia, Tien, Michelsen and Shelton have the world’s most precious commodity on their side: Time. Tennis is all about trying to take time away from the other player, to make them feel so rushed that they can’t breathe, between shots and between points.

Time is also a friend to younger players. They haven’t been around long enough to accumulate the scar tissue of losses and disappointment and unfulfilled dreams. Losses are learning experiences by default, rather than by mental force.

They also possess another priceless commodity in sports and in life: Hope. Fritz, Tiafoe and Paul still have plenty of that, but it’s a different flavor. Their decade-plus in pro tennis serves as a constant check. At this stage of their careers, their improvements are likely to be marginal yet could still bring massive reward.

“At some point, it’s not going to be me anymore,” Fritz said of being the top American in January.

“It’s a natural progression,” he said. “I’m getting old.”

No one would say that Tien and Michelsen are on their way to being old, but they have recently moved away from the coaches who guided them through their early pro careers, to work with seasoned tour veterans who know what it takes to get to the top. Tien hired Michael Chang, the 1989 French Open champion and a top-10 mainstay during the 1990s, in the middle of last season. Michelsen brought on Kristof Vliegen, a Belgian who helped Tallon Griekspoor rise from unranked nobody to the cusp of the top 20.

Vliegen, speaking last December as his charge sweated through a series of sprints, said Michelsen’s physical gifts — he’s 6 feet 4 with long arms, a huge serve and soft hands — made signing on with him late last year a no-brainer, even if his footwork needs some work.

“In October, when I was free, I had some calls. I said to everybody that I’m not looking for a guy who’s 32 years old. I’m looking for a young guy; it doesn’t matter the ranking. A young guy that I can see, that I can improve him or help him. I wanna be involved in the project that we have, and we will see how far we get with it.”

Time, health, luck and mental fortitude will play a role in determining that. Tennis-wise, Tien still looks to be the more finished project. He has smooth, crisp shots and plays with a precocious level of control, building points and jumping on chances to tag the back of the ball for a lacing winner down or across the court.

This has taken him to a series of impressive wins over top-10 players, but they tend to beat him the second time around, once they are familiar with the way he uses his left-handedness more effectively than just about anyone. Still, his mien helped him surprise opponents last year. He doesn’t look like the guy who is going to clean your clock on a tennis court. And then he does, shooting around the court like a cat, getting his feet behind the ball and cracking it away.

“Obviously, there are various aspects of his game that we are wanting to improve, like his serve (which has improved a lot in such a short period of time) and fitness,” Chang wrote in an email. “He has no big weaknesses in his game, so a lot of the focuses are on refining certain shots and making them better.”

At 5-11, Tien is undersized for a top pro these days and soft-spoken, halting at times in his speech, thinking before he speaks. He drives a small Tesla. Michelsen gets around in a BMW sport utility vehicle, which he acknowledges is not exactly the hottest look for a young and rising sports star. His mother uses the car to drive the rest of the family around when Michelsen is away.

“I’m a big guy,” he said. “It works for me.”

Each seeks some of what the other one has. For Tien, an outstanding mover who rarely makes a bad decision during a point, a year of hardcore fitness work, even during the season, has paid dividends. The puffy cheeks of his rookie year are gone.

To the naked eye, his service motion appears to have new pop to it. Strength and flexibility work have helped him learn how to snap his spine with greater force to add velocity.

“It’s been a pretty big focus of mine for a while,” he said in December, after collecting plenty of free points across two sets and the match tiebreak against Michelsen. “Baby steps.”

For Michelsen, who doesn’t rate his own serve all that highly — even though when he cracks it, it can sound like a thick tree branch snapping — the chase is not for velocity but rather accuracy and placement.

“The ball placement on every shot and just being a little more intentional,” he said. “I feel like I would just hit balls and not really think about where they’re going too much, and you’ve got to be a little bit more focused on the court. I feel that comes with some maturity for me as well.”

Then there is the footwork, which rarely comes naturally to someone his size. After Michelsen and Tien finished their two hours of practice, Rodney Marshall, Michelsen’s fitness coach — who occasionally also trains Tien — showed up and dropped the cones on the court.

For the next 40 minutes, Michelsen danced and sprinted around the court, with Marshall timing all his moves. Tien watched from the side, thankful he was on orders to keep his legs fresh for the Next Gen Finals. Still, he couldn’t resist jumping in for a mano-a-mano final sprint. Michelsen nicked him.

Vliegen liked what he saw. He knows the best players in the world right now are the best movers. He wants to help make Michelsen as big and as fast as he can, the sooner the better.

“He’s 21,” he said of Michelsen. “He’s gonna have his best years probably from his 24, 25, 26 years old. These are going to be the years where he’s going to be performing the best because he should be stronger mentally, should be stronger physically. You keep on building those things now, the chances are bigger that he’s going to have a good peak at those moments, and if we get the peak earlier, I’m not here to wait for three or four years.”

Tien’s and Michelsen’s similarities and differences make them a fascinating pair. They grew up close to each other in Orange County and spent their teen years competing and practicing with each other.

They estimate that they have hit more balls with each other than any other person. Michelsen is the rare pro who is unbothered by Tien’s left-handedness, even though most of his opponents are right-handed. A tennis ball is a tennis ball. He sees it. He hits it. It’s not that deep. Both are intensely competitive, though they disguise it in different ways. Like Vliegen, they do not want to wait, but they also recognize that they do not have much choice.

Michelsen might never move like Alcaraz. Tien probably won’t ever have the power of Sinner. For now, though, they have time — time to work and hope that it all comes together for them one day.

At the same time, here comes the spotlight, because the game moves. They want their time to be now. More and more, it’s looking like it will be.