To mark the end of another exciting season, ATPTour.com unveils our annual ‘Best Of’ series, which will reflect on the most intriguing rivalries, matches, comebacks, upsets and more. Today we highlight five notable Grand Slam comebacks from this season.
Taking down a top player is one thing, but doing it on his favorite surface, in front of a packed crowd – or even in your first Grand Slam match – is another.
From rising teenagers dismantling top seeds to qualifiers defying the odds on the sport’s biggest stages, the 2025 majors delivered drama few could have imagined. As part of our annual season reviews, ATPTour.com counts down the five most unexpected Grand Slam upsets of the year.
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5) Roland Garros R2: Gift d. Resitigis 6-4, 5-7, 6-2, 6-4
Stefanos Tsitsipas had made Roland Garros one of his happiest hunting grounds until Matteo Gigante stepped in.
Few expected the Italian qualifier, at number 167 in the PIF ATP rankings, to trouble someone from the clay-court elite. But Gigante, playing with the verve and fire of someone with nothing to lose, unleashed his explosive lefty forehand to topple the 2021 finalist in four sets. It was a loss that deeply affected Tsitsipas.
For the first time since 2018, the former world No. 2 and Nitto ATP Finals champion fell outside the Top 20, with his season later derailed by a back injury that limited him to just four more wins. Gigante’s entry into the third round was a defining moment, and the Italian has since risen to a career-high No. 125 as he continues his bid for a place in the Top 100.
Matteo Gigante takes his first Top 20 victory over Stefanos Tsitsipas at Roland Garros. Photo: Adam Pretty/Getty Images.
4) US Open R2: Collignon d. Ruud 6-4, 3-6, 3-6, 6-4, 7-5
For Raphael Collignon, New York became the city where promise and proof met.
A broken thumb had disrupted his goal of getting straight into Roland Garros, and until the US Open he had never won a main draw match at a major. But after beating Daniel Elahi Galan in his opener, Collignon produced the performance of his life to beat 2022 finalist Casper Ruud after three 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 so scared at the beginning, but I found my rhythm.”
It wasn’t all plain sailing for Collignon, however, as he served three double faults when serving for the match at 6-5 in the fifth, before finally converting his third match point. It was a win that catapulted him back into the Top 100 and gave him a strong finish to the year, which saw him defeat No. 8 Alex de Minaur in the Davis Cup and reach the semi-finals on home soil at the ATP 250 in Brussels.
Raphael Collignon reaches the third round at a major for the first time. Photo: Matthew Stockman/Getty Images.
3) Wimbledon R1: beef d. Zverev 7-6(3), 6-7(8), 6-3, 6-7(5), 6-4
After four hours and 44 minutes on Center Court, Arthur Rinderknech delivered the moment that would change the rest of his 2025 season. The Frenchman’s opener against third seed Alexander Zverev at Wimbledon was all about a mismatch, but he refused to play the role of underdog.
Rinderknech smashed 79 winners with ruthless aggression, taking it to Zverev from the first ball to the last to secure his first win over a Top 5 player. The turmoil became the springboard for a stunning second half of the season, which included a semi-final in Gstaad and a fourth-round appearance at the US Open. He later reached his first ATP Masters 1000 final in Shanghai, where he fittingly defeated Zverev again to improve to 2–0 in their Lexus ATP Head2Head series.
“It was a very important moment, probably the best tennis moment of my career,” Rinderknech said in October, speaking about his Wimbledon victory against Zverev. “Then several things worked out step by step. I feel like I’m on the right track and can now do what I want to do, the way I want.”
Arthur Rinderknech beats Alexander Zverev in five sets at Wimbledon. Photo: Corinne 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 prospects, but few expected him to defeat one of the sport’s fiercest ball-strikers in his first main draw match at a major.
Yet Fonseca used his calm aggression and heavy forehand to get past ninth-seeded Andrey Rublev in straight sets – a win that set the Margaret Court Arena ablaze and social media ablaze. For the 18-year-old Brazilian, who had won the Next Gen ATP Finals presented by PIF four weeks earlier, it was confirmation of months of hype after his meteoric rise in the 2024 season.
“I tried not to put pressure on myself by playing with a Top 10 man in a huge stadium,” said Fonseca, who was supported by many Brazilian fans in Melbourne. “[I was] I’m trying to call on the crowd to help me. I just enjoyed playing my game. That’s one thing about me: I play better in the important points, I go for my shots. That was the difference today.”
Joao Fonseca beats Andrei Rublev in straight sets at the Australian Open. Photo: William West/Getty Images
Although Fonseca lost to Lorenzo Sonego in his second round match, the young talent continued to prove himself throughout the 2025 season. He captured his first ATP Tour title in Buenos Aires in February and then won the ATP 500 crown in Basel, becoming the first Brazilian to win a title above ATP 250 level since Gustavo Kuerten in 2001.
1) Australian Open R2: Ten d. Medvedev 6-3, 7-6(4), 6-7(8), 1-6, 7-6(10-7)
Margaret Court Arena played host to two of the biggest upsets of the season, with American teenager Learner Tien delivering the second with his late-night marathon victory over three-time Australian Open finalist Daniil Medvedev.
Ten, competing as world number 121, seemed destined for a chapter of heartbreak rather than a breakthrough after failing to convert a match point in the third set. The tension escalated further into the night when Medvedev stepped up to serve for the match at 6-5 in the fifth, but Tien refused to wilt and showed a mix of courage and clarity – and even a touch of Medvedev’s own tactical acumen – to claw his way back and grab the biggest win of his career at 2.54am local time.
“I was definitely hoping it wouldn’t go to a breaker in the fifth set, but I’m just happy I won,” Tien said. “I know I made it a lot harder than it might have been… Losing the third was tough after playing for so long and having a match point.”
Student Ten beats Daniil Medvedev in five sets at the Australian Open. Photo: Paul Crock/Getty Images.
From that moment on, Tien’s trajectory only became steeper. Together with Fonseca, who defeated the American in the 2024 Next Gen ATP Finals presented by the PIF title match, Tien suddenly seemed completely at home at tour level. He has five Top 10 wins in 2025 according to the Infosys ATP Win/Loss Index, and captured his first ATP Tour title in Metz in November.
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