Denis Istomin defeated Mikhail Kukushkin 7-6 2-6 6-2 in the St. Petersburg round of 32 on carpet. The upset overturned the form book — Mikhail Kukushkin came in leading the head-to-head 5–2. Denis Istomin narrowed the head-to-head to 5–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2018-09-17 | St. Petersburg | R32 | carpet | Mikhail Kukushkin | 7-5 2-4 RET |
| 2016-05-02 | Madrid Masters | Q2 | clay | Denis Istomin | 6-2 2-6 6-3 |
| 2016-02-22 | Dubai | R32 | hard | Mikhail Kukushkin | 7-5 7-6(3) |
| 2016-01-04 | Brisbane | R32 | hard | Mikhail Kukushkin | 6-2 7-5 |
| 2015-01-11 | Sydney | R32 | hard | Mikhail Kukushkin | 6-3 7-6(1) |
| 2014-06-16 | Eastbourne | R32 | grass | Denis Istomin | 7-6(6) 6-7(7) 6-3 |
| 2012-09-14 | Davis Cup WG PO: KAZ vs UZB | RR | clay | Mikhail Kukushkin | 6-4 6-2 6-7(5) 6-2 |
Averages from each player's recent completed matches (20 vs 19). ATP, WTA & Challenger.