The Maryland native defeated Nadal 6-4 4-6 6-4 6-3 in a match that lasted over 3 hours and 30 minutes.
Tiafoe, 24, is the youngest American man to reach this far at the US Open, as Andy Roddick, then 24, was a 2006 finalist.
“It was definitely my best performance,” he said after the game. It helped that I played a few times with
Early in the tournament, Tiafoe said she was happy to be out of the spotlight.
“I had a huge passion for the game, mostly to do it for them, not for me. To see them experience me beat Rafa Nadal, They’ve seen me win big, but to them, I can’t imagine what was going on in their heads to beat the men of Mount Rushmore.
“Yes, I mean, they will remember this day forever.”
“I still don’t feel any pressure. I feel like I don’t have to do anything,” he said. “
Nadal, 36, recorded his first loss at a Grand Slam tournament this year and is 22-1 this season. The Spaniard won the Australian Open and the French Open before withdrawing from Wimbledon before his semifinal showdown with Australia’s Nick Kyrgios scheduled for July.
Tiafoe will face Russia’s Andrei Rublev in Wednesday’s quarterfinals.
The US Open men’s singles final is scheduled for Sunday.
Tiafoe’s parents met in the United States, where twins Franklin and Frances were born.
Their father signed up in 1999 as a day laborer at the Junior Tennis Champions Center in College Park. Working around the clock, his father was forced to move into an empty storage room at the tennis center. There, his two sons slept there with him while his mother worked the night shift as a nurse. Tiafoe started playing the sport and was able to play for free at the center and fell in love with the sport.
Tiafoe previously said his family didn’t grow up wealthy, but he wouldn’t change anything.
He told reporters on Monday: Tennis, which my father seemed to like, would be great if you guys could use this as a full scholarship to school.I mean, we couldn’t afford college.
CNN’s Jill Martin contributed to this report.