Young guns ignite 2025’s Grand Slam shocks
Amid the majors’ relentless pressure, a surge of teenagers and qualifiers unleashed upsets that toppled seeds, fueled breakout seasons, and hinted at a shifting tour dynamic.
The 2025 tennis season closed on a high note of unpredictability, with ATPTour.com’s annual ‘Best Of’ series recapping the year’s most gripping moments. Among them, five Grand Slam upsets stood out for their sheer audacity, as underdogs seized control on clay, grass, and hard courts. These victories, often against top seeds on favored surfaces, blended tactical precision with raw nerve, turning potential routs into career launches.
Qualifier storms clay fortress
On the gripping red clay of Roland Garros, Matteo Gigante confronted Stefanos Tsitsipas, a player who had made the tournament his stronghold since reaching the 2021 final. Ranked No. 167, the Italian qualifier played without the burden of expectation, firing his left-handed forehand inside-out to stretch the Greek wide and disrupt his baseline rhythm. Gigante’s aggressive one–two combinations—deep crosscourt shots followed by down-the-line backhands—secured a 6-4, 5-7, 6-2, 6-4 triumph, leaving Tsitsipas, the former World No. 2 and Nitto ATP Finals champion, reeling from his first fall outside the Top 20 since 2018.
The defeat deepened when a back injury hampered Tsitsipas, restricting him to four more wins that year. Gigante advanced to the third round, a milestone that boosted his ranking to a career-high No. 125 and sharpened his focus on cracking the Top 100. Crowds at Philippe-Chatrier sensed the shift early, their murmurs turning to roars as the underdog’s underspin slices neutralized the favorite’s topspin loops.
“It was a very important moment, probably the best tennis moment of my career,” Arthur Rinderknech reflected later in October about a similar breakthrough. “Then several things succeeded step by step. I feel I’m on the right track and I can now do what I want to do, the way I want.”
Shifting to the US Open‘s hard courts, Raphael Collignon overcame a broken thumb that had scuttled his Roland Garros entry. After edging Daniel Elahi Galan in the opener, he faced 2022 finalist Casper Ruud, whose heavy groundstrokes thrived on the medium bounce. Collignon’s deeper returns and inside-in forehands jammed Ruud in short rallies, clinching a 6-4, 3-6, 3-6, 6-4, 7-5 marathon after three hours and 28 minutes, even after three double faults while serving for the match.
The Belgian’s composure under Flushing Meadows’ night lights propelled him into the third round for the first time, vaulting him back into the Top 100. He built on that resolve with a Davis Cup upset over No. 8 Alex de Minaur and a semifinal at the ATP 250 in Brussels. These hard-court gains eased the mental strain of prior setbacks, allowing freer swings in pressure spots.
Grass aggressor flips the script
At Wimbledon, Arthur Rinderknech met third seed Alexander Zverev on Centre Court, where the German’s serve dominated the low-bouncing grass. The Frenchman countered with chipped returns to neutralize Zverev’s first delivery, then unleashed 79 winners via flat inside-out forehands that targeted the backhand side. After four hours and 44 minutes, Rinderknech’s relentless pressure yielded a 7-6(3), 6-7(8), 6-3, 6-7(5), 6-4 victory, his first over a Top 5 player.
The Centre Court crowd, initially hushed, erupted as the underdog’s slice approaches shortened points and forced errors. This win ignited Rinderknech’s summer surge, including a Gstaad semifinal, US Open fourth round, and a maiden ATP Masters 1000 final in Shanghai, where he defeated Zverev again to lead their head-to-head 2-0. Grass’s quick tempo suited his attacking style, transforming seasonal doubts into confident strides toward year-end contention.
These midseason shocks on varied surfaces underscored how mental resets could unlock potential, with underdogs thriving by adapting to each venue’s demands. Rinderknech’s tiebreak tenacity, in particular, echoed the grit needed to sustain momentum across a grueling tour.
Melbourne teens claim the spotlight
The Australian Open in January delivered two seismic upsets on Margaret Court Arena, starting with 18-year-old Joao Fonseca against ninth seed Andrey Rublev in his major debut. Fresh from victory at the Next Gen ATP Finals presented by PIF in late 2024, the Brazilian matched Rublev’s power with heavy forehands, varying flat drives and underspin to disrupt the Russian’s baseline stance. Fonseca’s composure in tiebreaks powered a 7-6(1), 6-3, 7-6(5) straight-sets win, drawing cheers from Brazilian fans under the arena’s lights.
“I was trying not to put pressure on myself, playing with a Top 10 guy in a huge stadium,” Fonseca said afterward. “I was trying to call the crowd to help me. I just enjoyed playing my game. That’s one thing about myself: I play better in the important points, I go for my shots. That was the difference today.” Though he fell next to Lorenzo Sonego, the triumph validated his rapid 2024 ascent and led to his first ATP title in Buenos Aires, followed by an ATP 500 crown in Basel—the first for a Brazilian above 250 level since Gustavo Kuerten in 2001.
“I think it’s the best day of my life,” Raphael Collignon shared after his US Open stunner. “It was not easy because Casper is a great champion. I was so scared at the beginning, but I found my rhythm.”
The arena’s drama intensified in round two, where No. 121 Learner Tien dueled three-time finalist Daniil Medvedev in a late-night saga. The American squandered a third-set match point and survived Medvedev serving at 6-5 in the fifth, using deep crosscourt returns and inside-out passing shots to mirror the Russian’s defense. Tien forced a super-tiebreak and won 6-3, 7-6(4), 6-7(8), 1-6, 7-6(10-7) at 2:54 a.m., his biggest career victory after three hours and 54 minutes of tension.
“I was definitely hoping it wouldn’t go to a fifth-set breaker, but I’m just happy to get a win,” Tien admitted. “I know I made it a lot harder than maybe it could have been. Losing the third was tough after playing for that long and having a match point.” Having lost to Fonseca in the 2024 Next Gen final, the teenager parlayed the upset into five Top-10 wins and his first ATP title in Metz by November. These Melbourne miracles, blending youth’s fearlessness with tactical borrowing from veterans, signaled a new wave ready to challenge the tour’s established order, promising fiercer rivalries in seasons to come.
