Guillermo Bujniewicz defeated Valentin Florez 3-6 6-0 6-2 in the Argentina F13 round of 32 on clay. The upset overturned the form book — Valentin Florez came in leading the head-to-head 1–0. Guillermo Bujniewicz claimed a first win over Valentin Florez in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2011-08-08 | Argentina F10 | R32 | clay | Valentin Florez | 4-6 6-2 6-0 |