Thiago Monteiro defeated Guido Pella 5-7 6-4 7-6 in the ATP Rio de Janeiro round of 32 on clay. The upset overturned the form book — Guido Pella came in leading the head-to-head 2–1, but Thiago Monteiro had been the form player, winning 2 of their last 4 on clay. Thiago Monteiro narrowed the head-to-head to 2–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2023-07-24 | Hamburg | R32 | clay | Guido Pella | 6-3 4-6 6-4 |
| 2023-03-06 | Indian Wells Masters | R128 | hard | Guido Pella | 3-6 7-5 6-2 |
| 2015-02-23 | Buenos Aires | Q1 | clay | Thiago Monteiro | 7-6(1) 3-6 6-2 |
Averages from each player's recent completed matches (20 vs 20). ATP, WTA & Challenger.