Valentin Florez defeated Guillermo Bujniewicz 4-6 6-2 6-0 in the Argentina F10 round of 32 on clay. The upset overturned the form book — Guillermo Bujniewicz came in leading the head-to-head 1–0. Valentin Florez claimed a first win over Guillermo Bujniewicz in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2007-08-20 | Argentina F13 | R32 | clay | Guillermo Bujniewicz | 3-6 6-0 6-2 |