Craig Simmons led the way for the Mariners with the ball to pull back the visitors at Lark Hill after they got off to a flyer when they won the toss and batted.
Midland was ahead of the game after the openers put on 80 and were 1-122 before the Mariners’ captain intervened.
He claimed his ninth five-wicket haul, the most by a Mariner in first grade, taking the first three wickets en route to 6-62 from 26.2 overs. Kyle Gardiner ripped out the middle order to snare 3-96 from 27 overs as spin claimed nine of the 10 wickets, with Midland-Guildford dismissed for 260.
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READ NOWAt stumps, Rockingham-Mandurah negotiated the last 13 overs of the day to be 0-26.
Tyler Robertson (16n.o.) and Mitch Green (8n.o.) will resume this Saturday and look to bat for as much of the first session.