Brian Dabul defeated Matias Oneille 6-3 6-2 in the Argentina F9 qualifying round on clay. The upset overturned the form book — Matias Oneille came in leading the head-to-head 2–1. Brian Dabul narrowed the head-to-head to 2–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2006-04-10 | Uruguay F1 | R32 | clay | Matias Oneille | 6-3 6-2 |
| 2006-03-13 | Argentina F1 | R16 | clay | Brian Dabul | 6-3 4-6 7-5 |
| 2003-09-01 | Argentina F3 | QF | clay | Matias Oneille | 6-2 7-6(4) |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.