Sean Thornley defeated Jiri Kosler 3-6 6-0 6-2 in the Greece F4 qualifying round on hard. The upset overturned the form book — Jiri Kosler came in leading the head-to-head 1–0. Sean Thornley claimed a first win over Jiri Kosler in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-10-19 | South Africa F1 | R16 | hard | Jiri Kosler | 6-2 6-1 |