Donald Johnson defeated Jason Cask 6-3 6-3 in the Australia 2 Masters 1 round of 32 on hard. The upset overturned the form book — Jason Cask came in leading the head-to-head 1–0. Donald Johnson claimed a first win over Jason Cask in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1991-08-12 | Australia 2 Masters 3 | QF | hard | Jason Cask | 6-2 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.