Frances Tiafoe survives Alex Michelsen thriller to claim US Open semi-final spot

The 28-year-old looked destined for an early exit after Michelsen, 22, claimed the opening two sets and moved to within one game of victory. The younger American had dictated proceedings for much of the afternoon and was serving for a place in the last four.

But Tiafoe refused to surrender, turning the contest around to prevail 5-7, 3-6, 7-5, 6-3, 7-6 (6) after four hours and 39 minutes.

The packed crowd, which had fallen largely quiet as Tiafoe struggled, erupted as his revival gathered pace, transforming the atmosphere into a raucous celebration. Tiafoe eventually raised his arms and thumped his chest as the stadium roared.

The victory also put the American into rare company. He became only the second man to win a major quarter-final in a deciding-set tiebreak after recovering from a two-set deficit, matching Andre Agassi's feat at the 2005 US Open.

Afterwards, Tiafoe shared a lengthy embrace with Michelsen, who was playing in his first Grand Slam quarter-final.

"I'm pumped about it," Tiafoe said. "I'm super excited about it, but I don't feel like it's, of course, I mean, this is a crazy match, so of course I'm extremely pumped up, but... I just want to continue. I just want to keep going.

"I have higher hopes for myself. So yeah, it's great [but] the tournament is still going. There's a lot more tennis to be played, a lot more sets to be played, and a lot more physical things to be done. We're going to enjoy this, but we got to keep going."

The American now stands one victory from his maiden major final, with another semi-final appearance no longer enough to satisfy his ambitions. 

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