Matias Oneille defeated Rafael Serpa Guinazu 6-3 6-0 in the Argentina 1 Masters 2 round of 32 on clay. Matias Oneille extended the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2000-07-31 | Argentina F8 | SF | clay | Rafael Serpa Guinazu | 6-4 3-6 6-4 |
| 2000-06-12 | Argentina 1 | R16 | clay | Matias Oneille | 6-4 7-6(3) |
| 2000-06-12 | Argentina 2 | QF | clay | Rafael Serpa Guinazu | 6-4 6-4 |
| 1999-07-31 | Argentina 2 Masters 4 | R16 | clay | Matias Oneille | 1-6 7-6 7-6 |