Tiafoe is hoping to reach the final at Flushing Meadows for the first time, following semi-final defeats by Alcaraz in 2022 and Taylor Fritz in 2024.
But it was a straight-set third-round loss to Jan-Lennard Struff in last year’s tournament which brought about a change in coach – and mentality.
“This time last year he was losing matches because of his fitness, now here we are four hours and 40 minutes into a match and he’s raining down the fastest serve of the match,” former Grand Slam doubles champion Ryan Harrison told Sky Sports.
“This is why he put the hard work in at the gym when nobody’s watching. At the end of last year when he was having to hear all the chatter about his commitment, things he wasn’t doing well – at 28 years old it’s so hard to make a change like that, and his willingness to go through the process.
“For him to go through all that work, to fight to put himself in this position its great to see.”
While it has taken until now for Tiafoe’s renewed work-ethic to bear fruit in a major, he is unequivocal when asked how he compares to the player that reached the last four previously in New York.
“I’m just a different person in general,” he said.
“Those two runs were great, something I will cherish forever, but I’m not that person who I was when I made one in 2022 and when I made one in 2024. I’m not that person.
“I think I’ve been so routine-oriented all year, just continuously on a routine. Ideally you want to make every day feel the same.”