Sergio Cortes defeated Gabriel Keymer 6-2 6-4 in the Chile Masters 1 round of 32 on clay. The upset overturned the form book — Gabriel Keymer came in leading the head-to-head 1–0, but Sergio Cortes had been the form player, winning 5 of their last 10 on clay. Sergio Cortes claimed a first win over Gabriel Keymer in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-11-16 | Chile F1 | QF | clay | Gabriel Keymer | 6-2 6-4 |