The Mariners have fallen well short of reeling in Subiaco-Floreat's target in WA Premier Cricket action.
Returning to one-day cricket in the first round after Christmas the Mariners were in the field first and Subi piled on 6-268 from 50 overs.
Aaron Burrage was the pick of the Mariners bowlers claiming three wickets.
Rockingham-Mandurah lost early wickets in the chase at 16,17 and 46 and were on the cusp of being bowled out cheaply.
Teague Wyllie (43), Samuel Day (40*) and Corey Wasley (27) all made starts but none were able to push on and make a big score.
The Mariners were bowled for 179 in the 44th over.
Next week it's more one-day cricket when Rockingham-Mandurah take on Wanneroo away from home.