Jolan Cailleau defeated Jonas Merckx 6-2 6-1 in the Belgium F5 qualifying round on clay. The upset overturned the form book — Jonas Merckx came in leading the head-to-head 3–0. Jolan Cailleau claimed a first win over Jonas Merckx in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2017-07-31 | Belgium F7 | R32 | clay | Jonas Merckx | 6-1 7-6(1) |
| 2017-07-03 | Belgium F3 | R16 | clay | Jonas Merckx | 7-6(1) 2-6 6-2 |
| 2014-08-04 | Belgium F10 | R32 | clay | Jonas Merckx | 6-2 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.