Juan Manuel Valverde defeated Guillermo Bujniewicz 6-4 7-6 in the Argentina F8 qualifying round on clay. The upset overturned the form book — Guillermo Bujniewicz came in leading the head-to-head 2–0. Juan Manuel Valverde claimed a first win over Guillermo Bujniewicz in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2010-04-26 | Argentina F4 | QF | clay | Guillermo Bujniewicz | 6-3 3-6 6-2 |
| 2006-08-07 | Argentina F11 | R16 | clay | Guillermo Bujniewicz | 6-4 6-2 |