Nathan Ponwith defeated Derek Pham 6-7 6-1 7-5 in the M15 San Diego 3 quarter-final on hard. The upset overturned the form book — Derek Pham came in ranked #1222, leading the head-to-head 1–0. Nathan Ponwith claimed a first win over Derek Pham in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2025-11-19 | M25 Austin 1 | R32 | hard | Derek Pham | 6-3 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.