World number 47 Shelton defeated Tiafoe 6-2, 3-6, 7-6 (9/7), 6-2 to make the last four of a major for the first time and become the youngest American man to do so in New York since Michael Chang in 1992.
“It doesn’t get much better than that,” the 20-year-old Shelton said of a first-time meeting with Djokovic that awaits him on Friday. “I feel like I left it all out here tonight. It was an emotional battle.”
Shelton saved a set point as he won a crucial third-set tie-break and pulled away in the fourth to settle a historic first Grand Slam quarter-final in the Open era featuring two African-American men.
“Sometimes you’ve got to shut off the brain, close your eyes and just swing, and maybe it was a little bit of that down set point and it end up working out,” said Shelton.
“Some may say clutch but I don’t know about that.”
The former college champion, who is coached by his father and former professional Bryan Shelton, arrived at his second US Open with a tour-level record of 12-20 this season.
He had failed to win multiple matches at any of the 18 ATP Tour events he had played since advancing to the quarter-finals in his Australian Open debut.
Ten of his 17 victories in 2023 have now come at Grand Slams. Shelton reached the second round at Wimbledon after losing his opening match at the French Open.
Shelton ran away with the first set after breaking last year’s semi-finalist Tiafoe in the fifth and seventh games.
Tiafoe responded with a single break in the second enough to level the match. The contest turned into a real back-and-forth struggle in the third set as the pair exchanged six breaks of serve.
Shelton shook off consecutive double faults in the tie-break as two set points passed by, smacking a blistering inside-out forehand to stay in the set and holding his nerve as Tiafoe cracked first.
It was a pivotal moment in the match as Shelton carried over the momentum into the fourth set, breaking right away and then once more for a 5-2 lead before shutting the door on Tiafoe.