PERTH has a massive task next week when the side chases an imposing 334 for victory against Rockingham-Mandurah.
On a typically flat Lark Hill pitch on Saturday, the Demon bowlers toiled hard, none more than Alex Calmy, who took his maiden five- wicket haul in First Grade with 5-102.
Second Grade is in a strong position at 3-70, seeking 151 for victory.
Akash Fotedar (4-56) and Dean Nelson (3-20) were the pick of the bowlers.
Opening bowler Cooper Carrington had his best day with the bat as his 76 n.o. saw Third Grade tally 240.
In Fourth Grade, the Demons are in a position to claim outright victory.
Jaiah Moore took 5-21 to bundle the Mariners out for just 60.
Paul Athienides, with 74, enabled Perth to go into day 2 on the weekend with a 124-run lead.
Jesse Messere scored 93 in the Under-17s and Regan Woodhouse took 6-9 in the Under-15s.