Swiss Dominic Stricker secured the biggest win of his career with a thrilling 7-5 6-7(2) 6-7(5) 7-6(6) 6-3 upset of Greek seventh seed Stefanos Tsitsipas on Wednesday to reach the third round of the US Open.
Playing in his first US Open main draw, world number 128 Stricker used a massive serve, booming forehand and solid net play during a gruelling four-hour encounter in which he broke the Australian Open finalist six times for his first top-10 win.
"I came out today pretty well. I felt good from the first set on. It was a tough battle but I am just super happy right now," said Stricker. "I am going to enjoy the rest of the day and then I will recover for the next round."
For Tsitsipas, who won an ATP 250 title in Los Cabos in early August but then went a combined 1-2 at Masters 1000 events in Toronto and Cincinnati, the loss marked another early US Open exit after falling in the first round last year.
Tsitsipas had a chance to serve for the match while leading 5-3 in the fourth set but Stricker stepped up with the break en route to forcing a decider where he consolidated an early break with a hold to love for a 3-0 lead that sent him on his way.
"I was down 3-5 and then I came back in the fourth set. I don't know how, but I did it somehow and then I kept playing very high level tennis. I am a bit speechless but it is a great day," said the 21-year-old Stricker.
"Such a great day for me, such a great win," Stricker added. "It gives me a lot of confidence and I think it is great to see from my team. We are working hard every day and it is so great to do that."