Rockingham-Mandurah are in pole position for full points in their two day clash with Bayswater-Morley.
The Mariners chose to bat first and were bowled out for 179 with just more than 20 overs left in the day's play.
Corey Wasley was the best of the batsman scoring 57 including seven fours and a six while Teague Wyllie started well with 42 before being dismissed.
Needing quick wickets the put the home side of the back foot the Mariners bowlers went to work Adam France striking early.
Coach Craig Simmons was introduced into the attack and ran through the Bears middle order claiming three wickets as Bayswater reached 5/50 at stumps.