1991 GTE U.S. Men's Hard Court Championships – Singles

Boris Becker was the defending champion, but lost in the final to Pete Sampras. The score was 7–6(7–2), 3–6, 6–3.

Seeds
The first eight seeds received a bye into the second round. • # 🇩🇪 Boris Becker (final)

• # 🇺🇸 Jim Courier (semifinals)

• # 🇺🇸 Andre Agassi (third round)

• # 🇫🇷 Guy Forget (second round)

• # 🇺🇸 Pete Sampras (champion)

• # 🇺🇸 David Wheaton (semifinals)

• # 🇪🇸 Emilio Sánchez (second round)

• # 🇷🇺 Andrei Cherkasov (quarterfinals)

• # Jakob Hlasek (quarterfinals)

• # 🇷🇺 Alexander Volkov (third round)

• # 🇸🇪 Anders Järryd (first round)

• # 🇺🇸 Patrick McEnroe (third round)

• # Ronald Agénor (first round)

• # 🇫🇷 Fabrice Santoro (quarterfinals)

• # 🇪🇸 Francisco Clavet (third round)

• # 🇸🇪 Christian Bergström (third round)