John Isner defeated Jack Sock 6-4 6-3 in the Nice round of 16 on clay. The result followed the form book — John Isner came in leading the head-to-head 5–3, defending last year's round of 16. John Isner extended the head-to-head to 6–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2021-07-26 | Atlanta | R16 | hard | John Isner | 7-6(6) 6-4 |
| 2016-10-31 | Paris Masters | QF | hard | John Isner | 7-6(6) 4-6 6-4 |
| 2016-04-04 | Houston | SF | clay | Jack Sock | 7-6(4) 6-3 |
| 2015-10-26 | Basel | R16 | hard | Jack Sock | 7-6(5) 6-3 |
| 2014-07-21 | Atlanta | SF | hard | John Isner | 7-5 6-4 |
| 2014-07-07 | Newport | QF | grass | Jack Sock | 6-4 7-6(4) |
| 2013-04-08 | Houston | R16 | clay | John Isner | 7-5 6-7(3) 7-6(3) |
| 2012-07-16 | Atlanta | QF | hard | John Isner | 7-6(7) 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 (200 vs 199). ATP, WTA & Challenger.