Guillermo Duran defeated Nicolas Jara Lozano 6-3 6-2 in the Argentina F4 qualifying round on clay. The upset overturned the form book — Nicolas Jara Lozano came in leading the head-to-head 3–1. Guillermo Duran narrowed the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2010-06-07 | Argentina F8 | R32 | clay | Guillermo Duran | 4-6 6-2 6-2 |
| 2009-05-11 | Argentina F5 | R32 | clay | Nicolas Jara Lozano | 7-6(2) 6-3 |
| 2008-12-08 | Argentina F18 | R32 | clay | Nicolas Jara Lozano | 6-3 6-3 |
| 2007-08-27 | Argentina F14 | R32 | clay | Nicolas Jara Lozano | 6-4 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.