Alexander Blockx made history Monday by becoming the first Belgian man to reach the quarterfinals of the US Open, defeating Argentina’s Francisco Cerundolo in four sets at Flushing Meadows. The 21-year-old Blockx, seeded 28th in his debut at the tournament, secured a 6-3, 4-6, 7-5, 7-5 victory over the 24th-seeded Cerundolo.

Blockx’s run at the US Open has been marked by resilience and determination, especially in Monday's match, where he battled a sharp rib pain that required medical intervention. “I was just holding on, to be honest,” Blockx said, acknowledging the difficulty of the match despite his early lead. He revealed that he was already under medication before the match and continued to receive treatment during play. The Belgian admitted he was close to retiring if he had lost the third set but managed to persist and ultimately improved his condition as the match progressed.

The match remained tightly contested after both players split the first two sets. At 5-5 in the third, Blockx faced a critical moment when he fell behind 0-40 on his serve but responded with powerful serves and strong groundstrokes to hold his service game and then break Cerundolo’s serve, taking the set. The fourth set stayed on serve until Blockx secured the decisive break in the final game, prompting him to fall to the ground in celebration as Cerundolo’s final shot sailed out.

“This morning I stepped onto this court for the first time to warm up and that felt unreal, so to play a match here and win a match here is even crazier,” Blockx said following the win. His progress marks a significant milestone for Belgian men’s tennis, as he began the year ranked outside the top 100 and had to qualify for the Australian Open earlier in the season.

Blockx’s next opponent will be Russian Karen Khachanov, who advanced to the quarterfinals by defeating 14th-seeded American Learner Tien in a five-set match. Khachanov, a former US Open semifinalist, notably upset third-seeded Felix Auger-Aliassime in the second round.

As Blockx continues his breakthrough at Flushing Meadows, his performance has drawn attention for both his skill and his perseverance amid physical challenges.