American Tommy Paul, the No 14 seed, defeated Portuguese Nuno Borges 7-6 (6), 6-3, 5-7, 5-7, 7-5 at the USTA Billie Jean King National Tennis Center in New York on Thursday to reach the third round of the US Open.
Paul, ranked No 14, will face Kazakh Alexander Bublik, the No 23 seed, next.
Ahead of his victory, the American won against Dane Elmer Moller (6-3, 6-3, 6-1).
Borges, ranked No 41, beat American Brandon Holt (6-4, 6-2, 6-3) in the previous round of the US Open.
New York (Grand Slam), other second-round results (USTA Billie Jean King National Tennis Center, hard, USD 90.000.000, most recent results first):
Alex De Minaur (8) beat Shintaro Mochizuki (Q): 6-2, 6-4, 6-2
Daniel Altmaier beat Stefanos Tsitsipas (26): 7-6 (5), 1-6, 4-6, 6-3, 7-5
Felix Auger-Aliassime (25) beat Roman Safiullin: 6-1, 7-6 (4), 7-6 (5)
Alexander Zverev (3) beat Jacob Fearnley: 6-4, 6-4, 6-4
Alexander Bublik beat Tristan Schoolkate (WC): 6-3, 6-3, 6-3
Jaume Munar beat Gabriel Diallo (31): 7-5, 6-3, 7-5
Jannik Sinner (1) beat Alexei Popyrin: 6-3, 6-2, 6-2
Flavio Cobolli (24) beat Jenson Brooksby: 5-7, 6-3, 6-4, 2-6, 7-6 (3)
Leandro Riedi (Q) beat Francisco Cerundolo (19): 3-6, 4-6, 6-4, 6-4, 6-2
Kamil Majchrzak beat Karen Khachanov (9): 2-6, 6-7 (4), 6-4, 7-5, 7-6 (5)
Denis Shapovalov (27) beat Valentin Royer (WC): 7-6 (6), 3-6, 7-6 (4), 6-3
Andrey Rublev (15) beat Tristan Boyer (WC): 6-3, 6-3, 5-7, 7-6 (4)
Chak Lam Coleman Wong (Q) beat Adam Walton: 7-6 (5), 6-2, 4-6, 6-4
Lorenzo Musetti (10) beat David Goffin: 6-4, 6-0, 6-2
Ben Shelton (6) beat Pablo Carreno Busta: 6-4, 6-2, 6-4
Zizou Bergs beat Jack Draper (5): W/O
Carlos Alcaraz (2) beat Mattia Bellucci: 6-1, 6-0, 6-3
Jan-Lennard Struff (Q) beat Holger Rune (11): 7-6 (5), 2-6, 6-3, 4-6, 7-5
Adrian Mannarino beat Jordan Thompson: 6-4, 6-7 (5), 6-3, 6-3
Luciano Darderi (32) beat Eliot Spizzirri (WC): 6-0, 7-6 (3), 2-6, 6-4
Frances Tiafoe (17) beat Martin Damm (Q): 6-4, 7-5, 6-7 (8), 7-5
Ugo Blanchet (Q) beat Jakub Mensik (16): 6-7 (2), 7-6 (5), 3-6, 6-4, 7-6 (7)
Arthur Rinderknech beat Alejandro Davidovich Fokina (18): 6-4, 3-6, 2-6, 6-2, 6-3
Cameron Norrie beat Francisco Comesana: 7-6 (5), 6-3, 6-7, 7-6 (4)
Benjamin Bonzi beat Marcos Giron: 2-6, 4-6, 7-5, 6-3, 6-4
Taylor Fritz (4) beat Lloyd Harris (Q): 4-6, 7-6 (3), 6-2, 6-4
Raphael Collignon beat Casper Ruud (12): 6-4, 3-6, 3-6, 6-4, 7-5
Tomas Machac (21) beat Joao Fonseca: 7-6 (4), 6-2, 6-3
Novak Djokovic (7) beat Zachary Svajda (Q): 6-7 (5), 6-3, 6-3, 6-1
Jiri Lehecka (20) beat Tomas Martin Etcheverry: 3-6, 6-0, 6-2, 6-4
Jerome Kym (Q) beat Brandon Nakashima (30): 4-6, 7-6 (2), 7-5, 3-6, 7-6 (8)