Juan Martin Aranguren defeated Matias Oneille 6-1 6-1 in the Uruguay F1 round of 32 on clay. The upset overturned the form book — Matias Oneille came in leading the head-to-head 1–0. Juan Martin Aranguren claimed a first win over Matias Oneille in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2003-08-18 | Argentina F1 | R16 | clay | Matias Oneille | 6-4 2-6 6-3 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.