Tommy Paul's arrival means four Americans have advanced to the round of 16 for the second straight year, but the world number one player is next up for the job.
The 14th seed reached the fourth round of this year's U.S. Open along with compatriots Frances Tiafoe, Taylor Fritz and Brandon Nakashima with a 6-7 (5), 6-3, 6-1, 7-6 (3) victory over Canadian qualifier Gabriel Diallo on Saturday at Louis Armstrong Stadium.
The 27-year-old Paul will face top seed Jannik Sinner, who beat Australia's Christopher O'Connell in straight sets, on Monday for a place in the quarter-finals.
Paul, Tiafoe, Fritz and Ben Shelton all reached at least the fourth round a year ago, although the latter lost in the semifinals to eventual champion Novak Djokovic.
The last American man to win a Grand Slam tournament was Andy Roddick at the 2003 U.S. Open.
Paul reached the quarter-finals at Wimbledon earlier this summer but his fourth-round loss last year was his best career result at Flushing Meadows.
