MELBOURNE, Australia — Over the course of about seven hours on Friday afternoon, the Australian Open morphed into an American tennis trout farm.

It was nearly impossible to watch a singles match without seeing a red, white and blue flag on the scoreboard, as two early-twenty-somethings and one teenager who looks even younger than his 19 years rumbled through the men’s draw and into the second week.

Did anyone have two Orange County boys, Learner Tien and Alex Michelsen, tearing into the round of 16?

They didn’t.

“I was down a set and a break in the first round of qualies,” Tien, the teenager in the group, said after he’d dusted Corentin Moutet of France in three sets. “To now be in the second week feels a little crazy,” he added.

Michelsen had got there first, putting out No. 19 seed Karen Khachanov in three sets.

Wins for American women sandwiched all this, with Emma Navarro getting through to the second week in her third consecutive three-set win to the start of the day. Madison Keys got there to end the night, beating friend, compatriot and Australian crowd favorite Danielle Collins.

All that was a little less surprising. Keys and Navarro have been there before, as has Coco Gauff. Tommy Paul’s best Grand Slam result came in Australia when he reached the semifinals in 2022, and he joined Gauff, Keys and Navarro with a routine win over Roberto Carballes Baena the previous day. Paul and Gauff then kept the American mojo rolling even further, winning their fourth-round matches over Alexander Davidovich Fokina and and Belinda Bencic.

Tien, 19 and Michelsen, 20, who will try to keep the vibes alive Monday in Melbourne, are on a rise that is the opposite of that. Michelsen has some past form: he made the third round in Melbourne last year and he has won a couple of first-round matches at the U.S. Open in the last two years, though not like this, knocking off two top-20 players in three matches.

Tien, a two-time national junior champion, had played two Grand Slam main draw matches before this week, a four-set loss to Arthur Fils at the 2024 U.S. Open, and a three-set loss to Tiafoe the year before. The third time was the charm. He beat Camilo Ugo Carabelli of Argentina in five sets

Then the draw handed him two matches against the arch antagonists of the ATP Tour, less a baptism of fire than a mind-bending trip into twisting shots, beguiling spins and the dark arts of tennis with the big boys. Tien took on fifth seed Daniil Medvedev for five sets and nearly five hours in a match that ended not long before dawn. Then came Moutet, who at two sets down reminded Tien that he still had to win a third one, which Moutet played as though hobbled by a hip injury on some points while scrambling across the court at full speed on others. Interesting times for a Grand Slam newbie.

“I didn’t really know what was going on with him,” Tien said in his news conference, still with one foot in the washing machine.

Add in Ben Shelton’s four-set win over Lorenzo Musetti, the Italian who had beaten him two times out of two, and a remarkable statistic appears: This is the first Grand Slam since 1993 with three American men under 23 in the second week. Tien and Michelsen are also the first pair of American men aged 20 or younger to reach the third round at a Grand Slam since the 2003 US Open when Andy Roddick and Robby Ginepri, Michelsen’s coach, did it.

It was America’s two most recent major finalists, Taylor Fritz and Jessica Pegula, who found the fourth round a bridge too far. Gael Monfils produced an immaculate four sets to knock out Fritz; Olga Danilovic produced two of the same to take out Pegula.

Yes, it’s a bit weird. But maybe it’s explainable.

In mid-November, Michelsen and Tien were banged up. The two close friends, who play Fortnite together in their spare time and who have trained at the same Orange County tennis academy the past four years, had just ended long seasons. They had the usual menu of sore joints from hitting too many balls for too long.

They didn’t boot up the console.

“They basically put the rackets down for two weeks and went to work,” Rodney Marshall, the Southern California tennis fitness guru who has been working with Michelsen the past year, said during an interview from Los Angeles Saturday.

Everyone calls Marshall ‘Rocket’. He’s one of those experts in sporting torture that American tennis players have trusted with making them faster and stronger and more durable for 15 years.

Marshall, Michelsen and Tien worked together twice a day, six days a week at the academy in California where they have trained together the past four years — and on the sands of Aliso Beach, Calif.

They only had a small window and they needed to figure out what sort of incremental gains they might be able to make. They wanted to gain strength in their lower bodies and fine-tune their movements, so they could get in and out of the corners of the court faster — an essential skill these days.

Tien, who’d missed three months during the first half of the year with a cracked rib, needed some more leverage from his left leg — his back leg on a forehand — to maximize the power he could unleash from his 5ft 11in frame. Michelsen, who is 6ft 5in, needed to get better at lowering his center of gravity and finding power from a squatting position.

Life became an endless series of isometrics and plyometrics. The isometrics (holding positions for long stretches) strengthen muscles and tendons; the plyometrics (jumping) build explosiveness.

Saturdays, they went to the beach — to do sprints. Marshall brought an American football and sent them on passing routes across the sand, with one acting as the wide receiver and the other as the cornerback.

“It was almost like they were cramming,” he said of Tien and Michelsen. “They really embraced the suffering.” If that line sounds familiar, it’s for good reason: four-time Grand Slam champion Carlos Alcaraz, 21, credited finding “joy in the suffering” for his French Open title last June.

Pretty soon, Tien was getting a little more oomph when smacking a tennis ball down the line. Michelsen was getting himself into a ground-level contortion and telling Marshall he could stay there all day. “I love it down here,” he’d yell.

“It’s a constant battle every day,” Michelsen said in an interview after his third-round win over Khachanov, his second win over a seed in six days.

“I look at Marin Cilic. He was like 6-6, and he was always so low. I’ve been trying to replicate that.”

Alex Michelsen’s explosiveness from the ground has been key to his run in Melbourne. (Adrian Dennis / AFP via Getty Images)

On the other side of the country, in Florida, Paul was going through a fitness block of his own with Fritz before the latter headed to southern California for tennis training. Frances Tiafoe, Reilly Opelka, Jacob Fearnley and several other pros were with Paul in Florida.

“A good group,” said Paul, who often talks NFL and NBA with Michelsen in the locker room. “He’s a crazy good competitor,” he said of Michelsen.

Paul said during an interview Friday that he is determined to play matches on his terms in 2025. He wants to move other people around this season, and not be the one getting moved around as much. That always seemed to happen last year when he ran into Carlos Alcaraz and Jannik Sinner. His fast-paced, front-foot tennis could hurt them for a little while. He won a set off Alcaraz at Wimbledon and went up 4-1 up on Sinner at the U.S. Open. But then they would force him behind the baseline, and out of the contest.

“Carlos moves unbelievably well when he has to, but if you look at him when he’s playing his best tennis, he’s dictating,” Paul said.

Shelton was in Orlando, doing his own thing. He was trying figure out how to go from being a below-average returner to someone who can get free points on his serve while stopping other guys from getting free points on theirs.

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From the pre-dawn hours Friday, when Tien was beating Medvedev in a match that ended at 2:56 a.m., until sunset Saturday, when Shelton bested Musetti in a fourth-set tiebreaker, the 23-and-under trio showed that the training was worth it.

Tien got back to his hotel after 4 a.m. He ate cold, stale pizza, and didn’t fall asleep until just before 7 a.m. He slept till about 1:30 p.m. before making his way back to Melbourne Park, where he hit tennis balls basically standing still for 45 minutes and endured massage and physiotherapy for five hours.

He was dead asleep by 11 p.m. “That was much needed,” he said.

Then he filleted Moutet, doing to the Frenchmen what Moutet had done to so many others over the years, minus the dark arts of delay and distraction.

“Incredible effort from him today,” Tien’s coach, Eric Diaz wrote in text message. “Body was not doing well. Impressive mental rebound as well.”

Learner Tien’s court craft has tied his opponents in knots. (Daniel Crockett / AFP via Getty Images)

Shelton had some rebounding to do as well. He’d watched his two losses against No. 16 seed Musetti over and over, reliving the Italian rolling a series of backhand passing shots down the line. Tied at 5-5 in a fourth-set tiebreak, Shelton hit an awful drop shot that sat up for Musetti’s fearsome running backhand. The point looked lost, but Shelton knew what to expect. He covered the line, stabbed a volley into the open court and served out the match.

He’d spent the afternoon keeping an eye on the other matches, especially Michelsen.

“Me and Alex are boys,” Shelton said in his news conference.

“I’ve texted him and told him he’s a dog after every match that he’s won because it’s true. He is a dog. I think that he’s going to be towards the top of the game very soon.”

With Shelton watching on, Michelsen effectively sealed his win over Khachanov with three huge points in the second-set tiebreak. All of them had roots in the off-season training block. He won the first with a curving 108mph second serve, a product of the leg strength and jumps. He took the second after sprinting to a ball outside the tramlines and whipping a forehand down the line. He won the third with his bread and butter, a powerful backhand down the line — with a little extra pop from all those medicine ball throws with Marshall and Tien.

As for Tien, Shelton can see a kindred spirit in his fellow left-hander, despite their diametrically opposite styles. Tien’s game is all about changing pace, floating balls deep to the back court and then suddenly attacking. His tennis is nothing like Shelton’s full-frontal assault, but Tien is breaking through here, out of nowhere, two years after Shelton did on the same courts.

“Not a bad place to have a breakthrough,” Shelton said. “On top of all the guys that are already at the top in the U.S., we have a lot more coming. It’s really starting to show itself.”

Indeed it is. The trout farm, a lot easier to create in a wealthy country with more than 300 million people, is doing what it is supposed to do. There were 33 Americans across the singles draws, more players than any other country. As the tournament moves into the quarterfinals, there are already two with safe harbor and potentially four more on the way.

Now comes the hard part: breaking the tape at the finish line as Gauff did in New York 16 months ago. That doesn’t require a trout farm. It requires a unicorn — and there are no farms capable of producing those.

(Top photo: Peter Staples / ATP Tour)