Ivo Heuberger defeated Julian Knowle 3-6 6-3 6-1 in the Houston q16 on clay. The upset overturned the form book — Julian Knowle came in leading the head-to-head 2–0. Ivo Heuberger claimed a first win over Julian Knowle in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2003-08-25 | US Open | Q128 | hard | Julian Knowle | 1-6 6-3 6-4 |
| 1996-10-19 | Switzerland 2 Masters 4 | SF | carpet | Julian Knowle | 3-6 6-1 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.