Both teams went into the match with 100 per cent records after two games – but it was newly-formed Rossvale who came out on top with a relentless performance to win 8-1.
The newly formed Bishopbriggs team dominated from the start and scored all their goals in the first half.
Within two minutes, Jemma McQuillan slotted the ball home to give the home team the early lead and as they continued the pressure McQuillan bagged herself her second.
Newly signed Josselyn Fletcher then also made it on the score sheet twice within 10 minutes and shortly after McQuillan secured her hat-trick.
Goal number six was a screamer from Yasmin Boyce who shot past the St Mirren keeper from 35 yards.
McQuillan then got her fourth and Rossvale’s seventh.
And just before half-time Fletcher completed her hat-trick to send Rossvale in at the break eight goals up.
The second half was a lot less eventful.St Mirren had a spell of possession which led to a goal for the away team, but there was no further scoring.
Vale are one of three teams with full points after three games and sit second in the league table, behind Renfrewshire Ladies on goal difference.
Next Sunday, Rossvale welcome Buchan Ladies to Petershill Park in the first round of the Championship Cup.