Alexander Blockx beat Francisco Cerundolo in four sets on Monday to become the first Belgian man ever to reach the US Open quarterfinals.
The 21-year-old Blockx, seeded 28th in his Flushing Meadows debut, out-lasted 24th-seeded Cerundolo 6-3, 4-6, 7-5, 7-5.
Blockx, who upset fifth-seeded Flavio Cobolli in the third round, backed up that win with a determined performance during which he received "magical medication" from the doctor to combat a "sharp pain in my rib.
"I was just holding on to be honest," Blockx said. "Even though I won that first set 6-3, it could have been the other way round."
The win marks the latest stepping stone for Blockx, who began the year outside the top 100 and had to qualify for the Australian Open.
After splitting the first two sets, Blockx and Cerundolo stood level at 5-5 when the Belgian fell behind 0-40 on his serve.
Blockx worked his way back with big serves and booming strokes, holding serve and breaking Cerundolo in the next game to take the third set.
A tight fourth set went with serve until Blockx gained the winning break in the final game, falling to the ground in delight when a shot from the Argentine landed 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
Blockx next faces the winner between unseeded Russian Karen Khachanov and 14th-seeded Learner Tien of the United States.
VAN DE ZANDSCHULP SAVES MATCH POINT IN FIVE-SET US OPEN TRIUMPH
Botic van de Zandschulp rallied from two sets down to beat Arthur Gea 3-6, 6-7 (0/7), 7-6 (9/7), 7-6 (7/3), 6-4 and return to the US Open quarterfinals on Monday.
The Dutch veteran denied 21-year-old Gea a slice of Grand Slam history. The French player had been vying to become the first men's lucky loser to reach a Grand Slam quarterfinal.
A dozen lucky losers – players who lost in qualifying but made it into the draw when someone withdrew – had made it to the round of 16 at this level, but none had gone further.
Gea, ranked 87th in the world, lost in the final round of qualifying but reached the main draw when 18th-seeded Casper Ruud withdrew with a back injury.
He nearly broke through, but the Netherlands' van de Zandschulp saved a match point in the third set and almost two hours later sealed a win that put him into the quarterfinals for the first time since 2021.
The five-hour, 13-minute marathon was just shy of the record-longest US Open match, Dan Evans's five-hour, 35-minute first-round victory over Karen Khachanov in 2024.
An exhausted van de Zandschulp told the crowd he didn't know how he did it.
"No clue actually," the 30-year-old said. "Crazy comeback – five hours, 15 minutes, still standing, so that's a good thing.
"I think this is probably even better than the first quarterfinal I made here," added van de Zandschulp. “It's been some tough years, but started to play better this year again.
"It hasn't really sunk in yet, but I think tomorrow it's going to be a great feeling."
Next up for van de Zandschulp could be top-seeded Alexander Zverev.
The Dutch player has some history with upsets at the US Open. In 2024 he stunned then third-seeded Carlos Alcaraz in straight sets in the second round.