1991 U.S. Men's Clay Court Championships – Singles

David Wheaton was the defending champion, but lost in the quarterfinals this year.

Jaime Yzaga won the title, defeating Jimmy Arias 6–3, 7–5 in the final.

Seeds
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.


 * 1) 🇺🇸 Michael Chang (quarterfinals)
 * 2) 🇺🇸 Derrick Rostagno (first round)
 * 3) 🇺🇸 David Wheaton (quarterfinals)
 * 4) 🇺🇸 Richey Reneberg (quarterfinals)
 * 5) 🇺🇸 Jimmy Arias (final)
 * 6) 🇺🇸 Scott Davis (first round)
 * 7) 🇵🇪 Jaime Yzaga (champion)
 * 8) 🇺🇸 David Pate (first round)