2018 US Open – Men's singles

Novak Djokovic defeated Juan Martín del Potro in the final, 6–3, 7–6(7–4), 6–3 to win the men's singles tennis title at the 2018 US Open. It was his third US Open title and 14th major title overall. Rafael Nadal was the defending champion, but he retired in the semifinals against del Potro in a rematch of the previous year's semifinal. Nadal and Roger Federer were in contention for the world No. 1 singles ranking; Nadal retained the top ranking after Federer lost in the fourth round.

This tournament marked the last major appearance for former world No. 3 and 2013 French Open finalist David Ferrer; he retired from his first round match against Nadal due to injury. This was also the first major since the 2017 Wimbledon Championships in which former world No. 1 Andy Murray participated, entering with a protected ranking. He lost in the second round to Fernando Verdasco.

This marked the first time in the tournament's history that seven former champions competed: Federer, del Potro, Nadal, Djokovic, Murray, Marin Čilić and Stan Wawrinka.

Peter Polansky became the first player in history to qualify for the main draw of all four majors as a lucky loser in a calendar year.

Seeds
All seedings per ATP rankings. • 🇪🇸 Rafael Nadal (semifinals, retired)

• Roger Federer (fourth round)

• 🇦🇷 Juan Martín del Potro (final)

• 🇩🇪 Alexander Zverev (third round)

•  Kevin Anderson (fourth round)

• 🇷🇸 Novak Djokovic (champion)

•  Marin Čilić (quarterfinals)

• 🇧🇬 Grigor Dimitrov (first round)

• 🇦🇹 Dominic Thiem (quarterfinals)

• 🇧🇪 David Goffin (fourth round)

• 🇺🇸 John Isner (quarterfinals)

• 🇪🇸 Pablo Carreño Busta (second round, retired)

• 🇦🇷 Diego Schwartzman (third round)

• 🇮🇹 Fabio Fognini (second round)

•  Stefanos Tsitsipas (second round)

• 🇬🇧 Kyle Edmund (first round)

• 🇫🇷 Lucas Pouille (third round)

• 🇺🇸 Jack Sock ''(second round)

• 🇪🇸 Roberto Bautista Agut (first round)

•  Borna Ćorić (fourth round)

• 🇯🇵 Kei Nishikori (semifinals)

• 🇮🇹 Marco Cecchinato (first round)

• 🇰🇷 Chung Hyeon (second round)

• 🇧🇦 Damir Džumhur (first round)

• 🇨🇦 Milos Raonic (fourth round)

• 🇫🇷 Richard Gasquet (third round)

• 🇷🇺 Karen Khachanov (third round)

• 🇨🇦 Denis Shapovalov (third round)

• 🇫🇷 Adrian Mannarino (first round)

• 🇦🇺 Nick Kyrgios (third round)

• 🇪🇸 Fernando Verdasco (third round)

• 🇷🇸 Filip Krajinović (first round, retired)