Juan Manuel Cerundolo delivered the biggest upset of the French Open after rallying from two sets down to shock world No 1 Jannik Sinner. The 24-year-old Argentine produced a stunning comeback victory, winning 3-6, 2-6, 7-5, 6-1, 6-1 to end Sinner’s 30-match winning streak and derail his bid for a maiden Roland Garros title and career Grand Slam.Juan Manuel Cerundolo of Argentina celebrates winning against Jannik Sinner of Italy after their second round men's singles tennis match at the French Open tennis tournament in Paris, Thursday, May 28, 2026. (AP Photo/Thibault Camus) (AP Photo/Thibault Camus)We found 10 interesting facts about giant-killer Cerundolo that might interest tennis fansPulled off biggest comeback of his careerCerundolo looked completely overmatched early against Sinner and trailed 5-1 in the third set before dramatically flipping the match around. As Sinner began struggling physically late in the third set, the Argentine took control and dominated the final two sets.The comeback instantly became one of the biggest shocks of the 2026 tennis season.Brother learned about the upset mid-matchCerundolo’s older brother, Francisco Cerundolo, was playing his own second-round match nearby when fans began yelling updates from the neighboring court."'Your brother is winning, your brother is winning,'" Francisco said spectators shouted to him during towel breaks.Francisco later admitted he initially had no idea what was happening while battling through his own comeback victory over Hugo Gaston."I had no idea," Francisco said. "I was suffering in my own match and people kept telling me, 'Your brother won, your brother won'."And I was thinking, 'Damn it, now I have to win too because I can't fail now.'"Hails from a tennis familyThe Cerundolo family has deep roots in the sport. His father, Alejandro “Toto” Cerundolo, was a professional player and respected coach, while his mother, Maria Luz Rodriguez, also played tennis before later working as a sports therapist.Francisco has also become one of the ATP Tour’s top-ranked players, giving the family two elite-level professionals competing at the highest stage.Sister is also a champion athleteJuan Manuel’s younger sister, Maria Constanza, became part of Argentina’s gold medal-winning field hockey team at the 2018 Youth Olympic Games.ATP title in his debut tourCerundolo announced himself to the tennis world in remarkable fashion back in 2021. Ranked No 355 at the time and only 19 years old, he won the Cordoba Open as a qualifier in his ATP Tour debut.He won eight matches in nine days during that breakthrough run on home soil in Argentina.Clay courts are his favoriteAs a left-handed player who grew up idolizing Rafael Nadal, Cerundolo naturally developed into a dangerous clay-court specialist. His heavy-spin forehand and high-bouncing baseline game are especially effective on slower surfaces like Roland Garros.It is also reportedly his favorite tournament on the calendar.Nearly cracked the ATP Top 50The Argentine entered Paris ranked No 56 in the world after recently reaching a career-high ranking of No 54. Before stunning Sinner, Cerundolo had already been in strong form after winning an ATP Challenger title in Bordeaux earlier this month.That run included victories over four Top-100 opponents.Already riding a winning streakWhile much of the attention entering Roland Garros centered on Sinner’s dominance, Cerundolo quietly arrived in Paris on a six-match winning streak across all levels. His confidence continued growing throughout the clay season before finally exploding onto the global stage with the upset of Sinner.Already had experience beating SinnerThe Cerundolo family was not unfamiliar with defeating the Italian superstar. Francisco owns two career wins over Sinner, including a clay-court victory in Rome back in 2023. That experience may have helped Juan Manuel believe the upset was possible even against the world No 1.Personal lifeDespite his growing tennis profile, Cerundolo has largely stayed away from public attention off the court. There is no public information regarding a girlfriend or relationship, and the Argentine is believed to remain heavily focused on tennis and training.He reportedly continues living in Buenos Aires surrounded by his close-knit, tennis-centered family.Emotional family celebrationBoth Cerundolo brothers ultimately advanced to the third round at Roland Garros - the first time they have both reached that stage together in Paris.Francisco later reflected emotionally on the achievement."I looked up and my family still wasn't there," he said. "I asked what happened and they told me he was two sets to one down. I said, 'Okay, good, he's fighting.'"After both victories were complete, the older brother summed up the family’s emotions."It's more than a dream," he said. "A huge pride for all the family."