NEW YORK, ⁠Sept 8 (Reuters) - Frances Tiafoe recovered from two sets and ⁠a break down to beat U.S. compatriot AlexMichelsen 5-7 ‌3-6 7-5 6-3 7-6(6) at the U.S. Open on Tuesday, reaching the semi-finals for a third time in a thrilling fightback.

Tiafoe appeared to have lost all ​the magic of his early campaign before ⁠wresting the momentum in the ⁠third set and clinching it with a forehand winner.He will next ⁠play ‌either eighth seed Ben Shelton or defending champion Carlos Alcaraz.

Tiafoe thrived in his beloved Louis Armstrong Stadium this ⁠weekbut struggled to hit his stride on the ​Arthur Ashe court, ‌sending four winners versus his opponent's 15 in the opening ⁠set, before ​handing over the critical break on set point.

Michelsen did some of his best work running up on the net in the second set, ⁠where he got the decisive break with ​a fine backhand strike, and he sent another shot down the line to break in the opening game of the third.

But Tiafoe ⁠dug in his heels, levelling it in the 10th game as Michelsen lost his poise, and the veteran slammed his foot on the gas with another break on set point before winningthe ​first three games of the penultimate set.

The ⁠two brought their best tennis to a nerve-searing final set, where ​the crowd sprang to their feet ‌as Tiafoe sealed the win beforeembracing ​an emotionalMichelsenafter closing out the four-hour and 38-minute contest.

(Reporting by Amy Tennery in New York; Editing by Jamie Freed)