Botic Van de Zandschulp matched the best run by any US Open qualifier in reaching the quarter-finals and hopes to shock Daniil Medvedev and equal more Grand Slam history.
The 25-year-old Dutchman upset 11th seed Diego Schwartzman of Argentina 6-3, 6-4, 5-7, 5-7, 6-1 after four hours and 20 minutes to book a last-eight match with Russian second seed Medvedev, a two-time Grand Slam runner-up.
"What I've done for me, it's amazing that I beat No. 11 here, especially in a match like this," Van de Zandschulp said. "It was my first time in a big stadium.
"The next match is maybe going to be on Arthur Ashe. Going to be even more people there, so I'm looking forward to it."
World number 117 Van de Zandschulp became the third qualifier to reach the US Open men's quarter-finals, matching Frenchman Nicolas Escude in 1999 and Luxembourg's Gilles Muller in 2008.
No Dutchman had reached a Grand Slam quarter-final in 17 years and not in 18 years at the US Open. Now he's one win from matching the best Slam runs by qualifiers, into the semi-finals five times, most recently at this year's Australian Open.
"I have to say when I'm playing against guys who are better, my level is also increasing," the Dutchman said. "So I prefer to play against better guys. I start playing better myself."
Instead of an early flight home, Van de Zandschulp will try to capture a Slam before playing for the Dutch at Uruguay in Davis Cup.
His apparel sponsor has helped with unexpected needs in New York.
"They have good laundry service here, so I can get it washed every day so I have enough stuff for the rest of the matches," Van de Zandschulp said.
The US Open debutante began playing Slams this year, winning once each at Roland Garros and Wimbledon.
After two US Open qualifying wins and ousting Spain's Carlos Taberner in five sets in his main draw debut, Van de Zanschulp rallied past Norwegian eighth seed Casper Ruud 3-6, 6-4, 6-3, 6-4, then beat Argentina's Facundo Bagnis 3-6, 6-0, 6-2, 6-2 and next Schwartzman.
"I knew I could beat players who are ranked 20 or 10 in the world," he said. "But I didn't do it like this often, this consistently. I'm showing some good tennis throughout the whole tournament. So that's new for me."
Van de Zandschulp is making the most of a career derailed by Covid-19.
"I started when I was 20 with playing because I had to finish school," he said. "I started to play good in challengers. When I was 150 and ready to play the Grand Slams and the qualifying, Covid started.
"With the points now it's tough to get up, and you really have to make a lot of points to increase ranking. I did pretty good this year but you didn't see it really in the rankings.
"Now I'm making so much points that I'm top 100."