| Champ: |  Steve Johnson |
| Runner: | Tennys Sandgren |
| Score: | 7–6(7–2), 2–6, 6–4 |
| Draw: | 28 (4 / 3) |
| Seeds: | 8 |
| Type: | singles doubles |
See main article: 2018 U.S. Men's Clay Court Championships.
Steve Johnson was the defending champion and successfully defended his title, defeating Tennys Sandgren in the final, 7–6(7–2), 2–6, 6–4.
The top four seeds received a bye into the second round.