Miguel Merz defeated Mark Greenan 6-4 6-4 in the Canada Masters 4 round of 16 on clay. The upset overturned the form book — Mark Greenan came in leading the head-to-head 1–0. Miguel Merz claimed a first win over Mark Greenan in two meetings, levelling the head-to-head at 1–1.
Merz M. took it in straight sets.
Clay: Merz M. leads 1–0 · Hard: Greenan M. leads 1–0
Miguel Merz beat Mark Greenan 6-4 6-4. Umpiry, "Miguel Merz vs Mark Greenan — Canada Masters 4 Round of 16", https://umpiry.com/match/1991-06-08/greenan-vs-merz-canada-masters-4-r16?utm_source=cite (as of 8 June 1991).