Mark Greenan defeated Miguel Merz 6-3 6-4 in the Caribbean 2 Masters 4 qualifying round on hard. The upset overturned the form book — Miguel Merz came in leading the head-to-head 2–0. Mark Greenan claimed a first win over Miguel Merz in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1991-06-08 | Canada Masters 2 | QF | clay | Miguel Merz | 3-6 6-3 6-4 |
| 1991-06-08 | Canada Masters 4 | R16 | clay | Miguel Merz | 6-4 6-4 |