Stefan Kozlov defeated Donald Young 6-4 6-4 in the Sarasota CH round of 16 on clay. The upset overturned the form book — Donald Young came in leading the head-to-head 3–0. Stefan Kozlov claimed a first win over Donald Young in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2021-01-04 | Delray Beach | Q2 | hard | Donald Young | 4-6 6-4 6-4 |
| 2017-03-06 | Indian Wells Masters | R128 | hard | Donald Young | 7-5 7-6(5) |
| 2016-07-11 | Newport | R16 | grass | Donald Young | 6-0 6-4 |
Each player's serve crossed against the other's return, converted to expected hold of serve. Recent completed matches, ATP, WTA & Challenger. About
Averages over each player's completed matches in the selected window (199 vs 169). ATP, WTA & Challenger.