Learners Tian En and Joao Fonseca’s biggest Grand Slam upsets of spring 2025 | ATP Tour
Best of 2025
#NextGenATP stars Tien and Fonseca in biggest Grand Slam upset of spring 2025
Gigante, Collignon, and Rinderknech also made the top 5
November 30, 2025
Daniel Puckett/Getty Images
Learner Tian defeated Daniil Medvedev in five sets at the Australian Open.
Jerome Coombe
To mark the end of another exciting season, ATPTour.com presents our annual “Best of” series, which will reflect the most interesting rivalries, games, comebacks, upsets and more. Today we highlight five outstanding Grand Slam comeback players this season.
It’s one thing to beat a top player, but it’s another thing to do it on their favorite surface, in front of a packed crowd – even in your first Grand Slam match.
From budding teenagers beating top seeds to overcoming difficult qualifiers on the sport’s grandest stage, the 2025 Grand Slam has delivered the kind of drama few could have scripted. As part of our annual season review series, ATPTour.com takes a look at five of the most unexpected majors of the year.
5) Roland Garros R2: Giant d． Tsitsipas 6-4, 5-7, 6-2, 6-4
Stefanos Tsitsipas turned Roland Garros into one of his happiest hunting grounds until Matteo Gigante kicked down the door.
Few expected that the Italian qualifier, ranked 167th in the PIF ATP rankings, would cause trouble for one of the clay-court elites. But Gigante unleashed his explosive left-hand forehand with the passion and enthusiasm of a man with nothing to lose, defeating the 2021 finalist in four sets. This is a heavy loss for Tsitsipas.
The former world number two and Nitto ATP Finals champion dropped out of the top 20 for the first time since 2018, while his season was later cut short by a back injury that limited him to just four more wins. Gigante’s run into the third round was a defining moment as the Italian has since risen to a career-high world ranking of 125 and continues to compete for a spot in the top 100.
Matteo Gigante” style=”width:100%;” src=”https://www.atptour.com/-/media/images/news/2025/11/18/14/09/gigante-roland-garros-2025-upsets.jpg?w=100%25″>Matteo Gigante earned his first top-20 victory at Roland Garros over Stefanos Tsitsipas. Photo: Adam Pretty/Getty Images.
4) US Open R2: Collignon d． Luther 6-4, 3-6, 3-6, 6-4, 7-5
For Raphael Collignon, New York became a city where promise and proof met.
A broken thumb derailed his goal of advancing directly to the French Open, and he had never won a major championship main draw before the U.S. Open. But after defeating Daniel Elahi Galan in the opener, Collignon put in the performance of his life and defeated 2022 finalist Casper Ruud after 3 hours and 28 minutes.
“I think this is the best day of my life,” Collignon said. “It wasn’t easy because Casper is a great champion. I was scared at first, but I found my rhythm.”
However, things were not all smooth sailing for Collignon. He made three double faults in the fifth game at 6-5 on serve and finally regained his third match point. The victory vaulted him back into the top 100 and set the stage for a strong year, during which he defeated eighth-ranked Alex De Minaur in the Davis Cup and reached the semifinals of the ATP 250 event on home soil in Brussels.
Rafael Collignon” style=”width:100%;” src=”https://www.atptour.com/-/media/images/news/2025/11/18/14/29/collignon-us-open-2025-upsets-2.jpg”>Raphael Collignon reaches the third round of a major for the first time. Photo: Matthew Stockman/Getty Images.
3) Wimbledon R1: Rinderknech d. Zverev 7-6(3), 6-7(8), 6-3, 6-7(5), 6-4
After playing four hours and 44 minutes on Center Court, Arthur Rinderknech delivered a performance that would change the rest of his 2025 season. The Frenchman’s Wimbledon opener against third seed Alexander Zverev was rife with mismatches but refused to play the role of the underdog.
Lindeknych blasted 79 winners with ruthless aggression, passing the ball to Zverev from the first to the last to secure his first win against a top-5 player. The upset served as a springboard for a stunning second half of the season, including a run to the semifinals in Gstaad and a fourth-round appearance at the U.S. Open. He then reached his first ATP Masters 1000 final in Shanghai and, fittingly, defeated Zverev again to improve his record to 2-0 in the Lexus ATP Head2Head Series.
“It was a very important moment, probably the best tennis moment of my career,” Lindeknecht said in October of his win over Zverev at Wimbledon. “And then a few things clicked. I feel like I’m on the right track and I can now do what I want to do, the way I want to do it.”
Arthur Rinderknech” style=”width:100%;” src=”https://www.atptour.com/-/media/images/news/2025/11/18/14/05/rinderknech-wimbledon-2025-upsets.jpg”>Arthur Rinderknech beats Alexander Zverev in five sets at Wimbledon. Photo: Colleen Dubreuil.
2) Australian Open R1: Fonseca d． Rublev 7-6(1), 6-3, 7-6(5)
Joao Fonseca arrived at the Australian Open as one of the tour’s most exciting rising stars, but few expected he would defeat one of the sport’s fiercest hitters in his first Grand Slam main draw.
But Fonseca used clinical aggression and a heavy forehand to defeat ninth seed Andrei Rublev in straight sets – a victory that sent excitement around the Margaret Court Arena and set social media ablaze. For the 18-year-old Brazilian, who won the Next Gen ATP Finals at PIF four weeks ago, it was validation of months of hype following his rapid climb into the 2024 season.
“I’m trying not to put pressure on myself, playing in a huge stadium with a top-10 player,” said Fonseca, who was supported by many Brazilian fans in Melbourne. “[I was] Trying to appeal to the crowd to help me. I just love playing my game. One thing about myself is I’m better at the important spots and I work hard on my shots. That’s the difference today. “
João Fonseca” style=”width:100%;” src=”https://www.atptour.com/-/media/images/news/2025/11/18/14/16/fonseca-melbourne-2025-upsets.jpg”>Joao Fonseca defeated Andrei Rublev in straight sets at the Australian Open. Photo: William West/Getty Images
Although Fonseca lost to Lorenzo Sonego in the second round, the young talent further proved himself in the 2025 season. In February, he won his first ATP Tour title in Buenos Aires and then won the ATP 500 event in Basel, becoming the first Brazilian to win an ATP title above 250 since Gustavo Kuerten in 2001.
1) Australian Open R2: Tian D. Medvedev 6-3, 7-6(4), 6-7(8), 1-6, 7-6(10-7)
Margaret Court Arena produced two of the most shocking matches of the season as American teenager Learner Tien used a marathon performance to win the second match late at night over three-time Australian Open finalist Daniil Medvedev.
The world No. 121 looked destined for a heartbreaking chapter rather than a breakthrough one after failing to regain match point in the third set. Tensions escalated further when Medvedev led 6-5 in the fifth, but Tenn did not back down, showing a combination of grit and clarity – and even some tactical savvy from Medvedev himself – to pull back at 2:54am local time to claim the biggest win of his career.
“I definitely hoped the match wouldn’t go to the fifth set, but I’m happy to win,” Tian said. “I know I made the game a lot more difficult than it could have been… Losing the third game after playing for so long and having match point was tough.”
Learner Field” style=”width:100%;” src=”https://www.atptour.com/-/media/images/news/2025/11/18/14/20/tien-melbourne-2025-upsets.jpg”>Learner Tian defeated Daniil Medvedev in five sets at the Australian Open. Photo: Paul Crocker/Getty Images.
Tian’s trajectory has only gotten steeper since then. Alongside Fonseca, who defeated the American at the 2024 Next Generation ATP Finals at the PIF Championship, Tian suddenly looks completely at home at tour level. He had five top-10 wins in 2025, according to the Infosys ATP Win/Loss Index, and won his first ATP Tour title in Metz in November.
