K. Boulter leads the head-to-head 2-0 since 2018 against K. Birrell, over 2 matches.
| Surface | K. Birrell | K. Boulter |
|---|---|---|
| Clay | 0 | 1 |
| Hard | 0 | 1 |
| Date | Winner | Score | Event |
|---|---|---|---|
| May 12, 2026 | K. Boulter | 2 - 0 | Paris · 1/16-finals · clay |
| Oct. 19, 2025 | K. Boulter | 2 - 1 | Tokyo · Final · hard |