Martin Vassallo Arguello defeated Rafael Serpa Guinazu 3-6 6-3 6-4 in the Argentina 1 Masters 1 round of 16 on clay. The upset overturned the form book — Rafael Serpa Guinazu came in leading the head-to-head 3–2. Martin Vassallo Arguello narrowed the head-to-head to 3–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2001-04-23 | Argentina F4 | QF | clay | Rafael Serpa Guinazu | 6-7(3) 6-4 7-5 |
| 1999-11-15 | Chile F4 | R16 | clay | Rafael Serpa Guinazu | 7-6 7-6 |
| 1999-10-11 | Paraguay F1 | R32 | clay | Martin Vassallo Arguello | 6-4 6-3 |
| 1999-09-20 | Bolivia F1 | R16 | clay | Martin Vassallo Arguello | 1-6 7-6 7-5 |
| 1999-07-31 | Argentina 2 Masters 1 | R16 | clay | Rafael Serpa Guinazu | 6-4 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.