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 (7-2) 3-6 6-4 7-6 (7-3).
The ever-entertaining Tiafoe then advanced when opponent Grigor Dimitrov was forced to retire injured.
Tiafoe led Dimitrov 6-3 6-7 (5-7) 6-3 4-1 when the Bulgarian, hampered by an apparent hamstring injury, ended the match.
“I didn’t want to end it like that, for me or the crowd. But Friday is going to be one hell of a day,” 20th seed Tiafoe said.
“It’s the biggest match of mine and Taylor’s life.”
It is a third major semi-final for Tiafoe and a first for Fritz, who had lost all four of his previous matches at this stage of a major.
He roared in delight after battling past German fourth seed and 2020 runner-up Zverev earlier on Tuesday.
“Today just felt different,” Fritz, 26, said.
“I really felt like it was my time to go a step further. It’s only fitting I’m doing it here on this court, at the Open, in front of this crowd.”
Fritz’s victory followed New Yorker Emma Navarro beating Paula Badosa to reach the semi-finals of the women’s singles.