Nicolas Pastor defeated Facundo Arguello 6-4 5-7 7-6 in the Argentina F20 qualifying round on clay. The upset overturned the form book — Facundo Arguello came in leading the head-to-head 3–1, but Nicolas Pastor had been the form player, winning 7 of their last 10 on clay. Nicolas Pastor narrowed the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2011-06-27 | Argentina F9 | SF | clay | Facundo Arguello | 6-1 6-1 |
| 2011-05-16 | Paraguay F1 | R32 | clay | Nicolas Pastor | 4-6 7-6(4) 6-3 |
| 2011-04-18 | Argentina F2 | F | clay | Facundo Arguello | 6-2 6-4 |
| 2010-10-25 | Argentina F21 | R32 | clay | Facundo Arguello | 6-3 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.