Leonardo Olguin defeated Walter Grinovero 7-5 6-0 in the Argentina 1 Masters 1 round of 32 on clay. The upset overturned the form book — Walter Grinovero came in leading the head-to-head 1–0, but Leonardo Olguin had been the form player, winning 5 of their last 8 on clay. Leonardo Olguin claimed a first win over Walter Grinovero in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-10-04 | Bolivia F3 | R16 | clay | Walter Grinovero | 7-6 6-3 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.