MELBOURNE, Australia — A telling moment occurred about an hour before midnight Tuesday, at the net on Rod Laver Arena.

Joao Fonseca, the 18-year-old Brazilian, had morphed from a promising prospect into a sensation over the course of a straight-sets upset of Andrey Rublev, the notoriously hotheaded No. 9 seed at the Australian Open. It was the sort of loss that in the past had sent Rublev into paroxysms of despair, drawing blood as he smashed his racket into his knees.

None of that happened on this occasion, and not just because the Russian has put serious work into controlling his emotions.

Rublev, a 27-year-old veteran of the ATP top 10 who can blast with the best of them, grabbed Fonseca for a warm congratulatory embrace, but not before laughing with a grin as wide as the net as he whacked his racket onto the tape across the top of that divide, giggling at the absurdity of another kid blowing past him just as Carlos Alcaraz and Jannik Sinner have done in recent years.

These new guys will do that to you.

“Power has taken over now,” Stefanos Tsitsipas, who is the same vintage as Rublev, said the previous day after suffering through a first-round thumping from Alex Michelsen, another young buck.

Not so long ago, Tsitsipas, a two-time Grand Slam finalist, was that guy. He blasted his way past Roger Federer at this very tournament in 2019, seemingly heralding a new era. He had wins over Novak Djokovic and Rafael Nadal that didn’t demand the impossible of him.

“I didn’t have to exceed the most extreme version of myself,” the 26-year-old said, longing for those halcyon days. “It was still physical, but it was not as big as it is now.”

On Wednesday, Jakub Mensik, a Czech with a gigantic serve and soft touch, knocked out Casper Ruud, the No. 6 seed who has spent the past month or so telling anyone who will listen how sure he is that his brand of tennis is not long for this world. It’s the first time since 2006 that two top-10 ATP players have lost to teenagers at a Grand Slam. Those teenagers were Novak Djokovic and Andy Murray. They did OK in their careers.

If you want to win now, as Tsitsipas says, you better have both precision and power, like all these kids seemingly do — or you are dead.

Four days in, the men’s singles at the 2025 Australian Open has become a tennis version of Love Island: nearly every day, a new bombshell enters the villa.

Pick your favorite. Is it Mensik; or one of the two Southern Californians, Michelsen and Learner Tien. Is it one of the French Arthurs, Fils and Cazaux; or Fonseca, the Brazilian who before too long may drag an entire continent back to the forefront of this sport.

“It’s definitely getting faster,” said Sebastian Korda, who is just 24 years old but feels like an old-timer suddenly. “Footwork, speed, everything is just lightning. The way that Alcaraz moves, it’s insane how fast he is. I think everyone is super-athletic. Everyone is sliding off their right and left foot, like Sinner is. It’s just becoming very tricky to get the ball by guys.”

Korda has a unique perspective, having missed the better part of two years with a series of injuries. Coming back, he knew he was going to need to grow his skill set. “It’s a chess match right now. You’ve got to figure out ways to win points and it’s becoming harder and harder, for sure.”

The new crew have youth on their side, but they have something else, too. They’ve been coming of age and putting the seasoning touches on their games in the era of Alcaraz and Sinner, knowing all along that power, physicality and aggressive, first-strike tennis is the new meta and that return prowess is mightier than a serve. They press forward at any given opportunity; carve and chip and block their returns onto the baseline or awkwardly short in the court and disparage the idea of a neutral ball.

Unlike players just a few years older than them, who honed their skills to match up against the baseline mastery of Nadal, Federer and Djokovic and developed monster serves and counterpunching groundstrokes but not so much feel and geometric expertise, this group don’t have to reverse-engineer themselves to meet the moment. They’ve been training for this all along.

Listen to Eric Diaz. He’s the coach of Tien, the 19-year-old Vietnamese-American who was a junior finalist here in Melbourne two years ago, a match that was basically a three-hour rally with a Belgian named Alexander Blockx (who will probably be in a main draw near you sometime soon).

Tien was a lean and soft 17-year-old who had spent the previous two years figuring out how to hang with the big boys. He’s 5 feet 11 inches (180cm) now, and not stocky. But Diaz said he possesses the phenomenal foot and hand speed required to take a whack at a lot of balls that other players might have to hack away at while off-balance.

“He’s committed to trying to tag some balls and stay through it, as opposed to the typical lefty who hits that kind of loopy ball,” Diaz said after Tien won his first Grand Slam main-draw match Tuesday, beating a 25-year-old Argentine named Camilo Ugo Carabelli.

“He committed to trying to develop weapons.”

GO DEEPER

Carlos Alcaraz and Jannik Sinner are redrawing the tennis court

Tien said one of his biggest goals for this new year is to get stronger, but while he’s working on that, his brain can make the decisive difference in how the ball comes off his racket. He couldn’t match Carabelli in winners, posting 44 across five sets compared with 52, but when the match was on the line in the second half of its fourth hour, he kept firing at the line at the first chance he saw.

“I’m trying to impose myself more by using my forehand,” he said. “I’m trying not to have a neutral kind of form, but to be able to take offense and really set myself up in these points.”

He started doing that at the ATP Next Gen Finals just a couple of weeks ago, after Fonseca blew him off the court in the group stage. Tien reached the final and played Fonseca again. He lost again, but it was closer and he was hitting the lines more.

Mensik, another 19-year-old, is at the other end of the physical spectrum from Tien. He’s listed at 6ft 4in, and has the wingspan of someone even bigger. Competitors say he already has one of the best serves in the game, even as he has struggled with an elbow injury in his first full season of top-level tennis.

He heard what Tsitsipas said about needing both power and precision and thought, ‘I’m that player.’ He showed as much in taking out Nikoloz Basilashvili, the 32-year-old from Georgia, in four sets Monday, before eliminating Ruud. Mensik won the first set in 22 minutes, as Basilashvili struggled to keep up with Mensik’s pace.

It all felt very normal to Mensik, who watched Sinner and Alcaraz breaking through along with the rest of his contemporaries and came to the same conclusion.

“When I played the juniors, all of them were playing like that,” he said. “It’s obvious.”

Mensik is one of several young players aiming to break into the top of the ATP Tour. (Clive Brunskill / Getty Images)

As the final member of the ‘Big Three’ still on tour after the retirements of Federer and Nadal, Djokovic has gotten his share of this so-called next next generation.

First came Nishesh Basavareddy of the United States, a 19-year-old who has been a pro for a whole month now. He outplayed Djokovic for a set and a half, before fading physically. He still showed plenty to impress the greatest player of the modern era. Then came 21-year-old Jaime Faria of Portugal, who evened their match at a set apiece by blasting serves and finding holes to hit through Djokovic’s defenses, something countless players of Tsitsipas’ generation have failed to do so many times. He even took a tiebreak off the long-time world No. 1, who rarely loses those against less experienced players.

“At one point, he was making everything from baseline — serves, returns,” Djokovic said of Faria. Going into those matches, Djokovic knew both players might buckle under the pressure of the moment. They didn’t, instead feeding off the energy and finding a way to play what he called “lights-out tennis.”

Djokovic said he had also caught the end of Fonseca’s win — and admitted he’d been keeping an eye on him the past year. “I just love how he plays the big points, courageous, very clean hitter, all-around player,” he said.

The 37-year-old Serbian sees a little bit of himself in the young Brazilian: a kid who will go for his shots even when he probably should not, just to show off a little bit. “He’s got the goods, definitely — he showed that last night on a big stage — to go very far. The future is bright for him.”

Next for Fonseca is Lorenzo Sonego, a 29-year-old Italian who will have to hope that wisdom and guile win out over the exuberance of youth. Fonseca, who traded with Rublev for 12 games before playing the kind of supernova tiebreak under pressure that makes tennis fans’ hair stand up on their necks, said his goal for this trip to Melbourne was simply to survive qualifying. He fell a set short of that four months ago at the U.S. Open, overwhelmed by a hometown (kind of) crowd that rallied around his American opponent Eliot Spizzirri, from the nearby state of Connecticut.

Against Rublev, in what was his first main-draw match in a Grand Slam, he believed he had a chance, even though his opponent has been a mainstay of the top 10 for the past three years. When he then won the first two sets, Fonseca knew the match was on his racket. The nerves arrived, but he stayed focused.

Now he is dreaming bigger.

“I want more and more,” he said. “I think that’s the mentality of the champion.”

(Top photo: Asanka Brendon Ratnayake / Associated Press)