Frances Tiafoe, a US Open semi-finalist twice in the past three years, crashed out in straight sets to Germany's Jan-Lennard Struff in the third round on Friday.

Struff came through the qualifiers to reach the main draw and continued to upset the odds, taking out 17th seed Tiafoe 6-4, 6-3, 7-6 (9/7) to make the last 16 in New York for the first time.

The 35-year-old Struff defeated Danish 11th seed Holger Rune in the previous round and could face 24-time Grand Slam champion Novak Djokovic for a spot in the quarter-finals.

The German had not won a match at Flushing Meadows before this tournament since reaching the third round in 2020.

Tiafoe's exit was his earliest at the US Open since a second-round loss in 2019. His defeat came shortly after fellow American and sixth seed Ben Shelton retired from his match on Friday with a shoulder injury.

Andy Roddick's 2003 US Open victory is the last men's major won by an American player.