Alison Riske defeated Shuai Zhang 7-6 4-6 6-1 in the Australian Open round of 64 on hard. The upset overturned the form book — Shuai Zhang came in leading the head-to-head 2–1, defending last year's quarter-final. That levelled the head-to-head at 2–2.
Riske A. came through in three sets.
Riske A. and Zhang S. faced 3 of the same opponents in the last 12 months. Riske A. went 0–3 (0%) against them, Zhang S. 4–2 (67%). Zhang S. came out better against 3 of 3 comparable opponents, Riske A. against 0 — though 1 of those edges carries caveats (retirement).
Only 3 common opponents — small sample, treat as indicative.
Alison Riske beat Shuai Zhang 7-6(7) 4-6 6-1. Umpiry, "Alison Riske vs Shuai Zhang — Australian Open Round of 64", https://umpiry.com/match/2017-01-18/riske-vs-zhang-australian-open-r64?utm_source=cite (as of 18 January 2017).