Sloane Stephens defeated Simona Halep 6-1 6-1 in the Australian Open round of 128 on hard. The upset overturned the form book — Simona Halep came in leading the head-to-head 7–1, defending last year's round of 128. Sloane Stephens narrowed the head-to-head to 7–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2018-08-06 | Montreal | F | hard | Simona Halep | 7-6(6) 3-6 6-4 |
| 2018-05-28 | Roland Garros | F | clay | Simona Halep | 3-6 6-4 6-1 |
| 2017-08-14 | Cincinnati | SF | hard | Simona Halep | 6-2 6-1 |
| 2017-07-31 | Washington | R32 | hard | Simona Halep | 7-6(3) 6-0 |
| 2015-03-23 | Miami | QF | hard | Simona Halep | 6-1 7-5 |
| 2014-05-26 | Roland Garros | R16 | clay | Simona Halep | 6-4 6-3 |
| 2013-01-07 | Hobart | R16 | hard | Sloane Stephens | 6-4 6-0 |
| 2012-04-09 | Barcelona | R32 | clay | Simona Halep | 6-4 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 198). ATP, WTA & Challenger.
Performance in the biggest moments — break points, deciding sets and tiebreaks (0–100, higher is better). About