Frances Tiafoe set up a US Open semi-final against Taylor Fritz to guarantee there will be an American man in the singles final in New York for the first time in 18 years.
Andy Roddick was the last American man to win a Grand Slam singles title when he triumphed at Flushing Meadows in 2003.
Roddick was also the last American man to reach a US Open final, having lost to Roger Federer there in 2006.
But the wait for a home finalist will soon be over after Fritz ended his run of Grand Slam quarter-final disappointment by edging out Alexander Zverev 7-6, 3-6, 6-4, 7-6.
The ever-entertaining Tiafoe then advanced when opponent Grigor Dimitrov was forced to retire injured.
Tiafoe led Dimitrov 6-3, 6-7, 6-3, 4-1 when the Bulgarian, hampered by an apparent hamstring injury, ended the match.
On the women’s side, Aryna Sabalenka sent an ominous message to her rivals as she demolished Zheng Qinwen to set up a US Open semi-final against Emma Navarro.
World number two Sabalenka claimed a statement 6-1, 6-2 victory against Olympic champion and seventh seed Zheng.
That came after American Navarro recovered from a 5-1 second-set deficit to beat Spain’s Paula Badosa 6-2, 7-5 in front of a partisan New York crowd.
Belarusian Sabalenka reached the final last year, losing to Coco Gauff, but she looks in superb form to claim another Slam title to go with her two Australian Open triumphs.