Jeff Loehr defeated Antonio Prieto 7-6 6-1 in the USA F4 round of 32 on clay. The upset overturned the form book — Antonio Prieto came in leading the head-to-head 1–0. Jeff Loehr claimed a first win over Antonio Prieto in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-01-04 | USA F1 | R64 | hard | Antonio Prieto | 6-2 6-1 |