Blacktown are three runs away from claiming first innings points when play resumes in their Sydney grade cricket match at Joe McAleer Reserve this Saturday.
Blacktown are 7-110 in reply after bowling Mosman out for 112. Matt Foster led the way with five wickets with the help of captain Tony Clark, who grabbed a handy three.
Clark and top run-scorer Michael Bright (37) are the not-out batsmen with Blacktown poised to snare first innings points for the second time in as many games this season.
Meanwhile, Penrith will rely on their bowlers to get them out of jail in their clash against Campbelltown Camden at Raby Oval.
Penrith were 9-110 when rain stopped play.
Stuart Finemore (33), Mathew Halse (20) and Ryan Gibson (17) were the only Penrith batsmen to reach double figures.
In the lower grades, Penrith second grade batted first and scored 133 and both thirds and fourths posted competitive totals of 182 while fifths are 0-12 chasing 160.
Blacktown thirds posted 159 at Jim Hanshaw Oval with Mosman 2-42 while fifths are 0-4 chasing 178 at Whalan Oval.
There was no play for Blacktown seconds or fourths because of the weather.
The Twenty20 competition begins on Sunday. Blacktown host Hawkesbury at Joe McAleer Oval at 2.30pm. Penrith host North Sydney at Howell Oval.