Jordan Mast finished 81 not out as his side built an imposing total of 290 all out at Tompkins Park on Saturday.
Midland-Guildford were 3-19 before the impressive Aneurin Donald (62) combined with Keaton Critchell who managed 34 in a 100-run stand.
Melville are 0-4 at the close of play, as the Monkey Towners look to build on their new-found momentum.
In Sunday’s T20 match, Midland-Guildford lost to University by seven wickets at Lilac Hill.
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In Sunday’s Female A-Grade T20 competition, Midland-Guildford defeated Subiaco Floreat by six wickets at Alderbury Reserve.
Perth Scorchers batswoman Chloe Piparo (34no) warmed up for the Women’s Big Bash League by leading the run chase.