Draper broke the Czech star six times to win 6-3, 6-1, 6-2 in just an hour and 44 minutes – setting up a final eight battle with 10th seed Alex de Minaur.

The result sees him go one better than his fourth round exit last year at the US Open, making this his career-best Grand Slam performance.

In what appeared to be a tough match up for the British star on paper against a player he’s lost to on all three previous meetings, Draper brought his best level of the week so far and is the only player left in the draw yet to drop a set.

“I thought the last few times we played it’s been a really tough battle,” Draper said in his post-match on-court interview. “I think today he was a little bit off his best but I had to stay strong in the points.

“It’s just amazing to play out here on Louis Armstrong. I lost last year here in the same round so it’s nice to come back and do better this year.

“I feel amazing, being in the last eight, my first quarter-final – it means the absolute world to me.”

Mahac made a promising start to the match, dropping just one point on his opening three service games, but one poor game in which he hit four unforced errors gave Draper the first break of the match and with it set the wheels in motion for a stunning victory.

Despite the frustration and chat between Mahac and his coach, Draper didn’t let his concentration slip. He found great success on his groundstrokes, particularly when pushed out wide, and came into the net more as well – contributing to his 35 winners.

With the match on the line he held off five break points at 4-1 and 5-2 to eventually round off one of the biggest results in his career.

“I just need to keep going. I’ve got some amazing people around me. I love playing here in New York in front of such amazing fans who always get behind and support the players.

“I just go for it again, I love playing on these big stages. I look forward to it and playing here again on Wednesday.”

Draper is the fifth British man to reach the quarter-finals at Flushing Meadows in the Open Era after John Lloyd, Greg Rusedski, Tim Henman and Andy Murray.

After a significant win in his career, Draper once again paid tribute to his friend and idol Murray in his first Grand Slam without the former world No.1.

“I obviously miss Andy, shout out to Andy, what an unbelievable career he’s had,” Draper said.

“He’s an icon in the game – I miss him in the changing rooms, I miss being next to his stinky shoes and stinky clothes. Andy is a legend and if I have half the career he’s had I’ll be a happy man.”

Draper will play his quarter-final match against De Minaur on Wednesday.