Taylor Fritz, the highest-seeded American men's player at No. 12, comfortably advanced to the US Open round of 16 on Friday.
Fritz took down Argentina's Francisco Comesana 6-3, 6-4, 6-2.
In doing so, Fritz became the first American man to make the round of 16 at all four majors in a year since Andre Agassi in 2003.
As Fritz was finishing up play on Louis Armstrong, fellow Americans Ben Shelton and Frances Tiafoe were locked in a five-set battle at Arthur Ashe Stadium, looking to join him in the second week.
In other men's singles matches Friday, both No. 6 seed Andrey Rublev and No. 9 Grigor Dimitrov carved out easy straight-set wins to set up a fourth-round showdown Sunday.
ESPN Stats & Information and Reuters contributed to this report.
