The forward, who is on loan with the Shakers until January, opened the scoring on 28 minutes, latching onto a Jordan Sinnott pass to score at the far post.
Sinnott himself got amongst the goals before the break and a third was added three minutes from time by substitute Marlon Jackson, six minutes after he had replaced Forrester.
It was the battle of the Rovers defenders at Spotland as Jack O'Connell's Rochdale took on Ryan Edwards' Chesterfield.
Both players started the match in which Rochdale came from behind to lead but had to settle for a point in an entertaining encounter.
Former Rovers youngster Marc Richards opened the scoring for the visitors on 19 minutes but Rochdale levelled from the penalty spot ten minutes later through Andrew Tutte.
Scott Hogan gave Dale an early second half lead but Chesterfield hit back to share the points thanks to Gary Roberts.
O'Connell played the full match for Rochdale, whilst Edwards was replaced just before the hour mark.
Dundee United had to settle for a point at Easter Road as Hibernian came from behind to draw 1-1.
Stuart Armstrong had given the Tannadice club the lead on the half hour but the visitors couldn't hold on as Scott Robertson levelled with eight minutes remaining.
David Goodwillie played just over an hour for United.
Skrill Conference North side Stalybridge Celtic got their league campaign off to the worst possible start with a 4-0 home defeat to Hednesford Town.
Goalkeeper Matty Urwin was beaten four times - once from the penalty spot - as Celtic tasted a heavy defeat.
Also beaten heavily was Skrill Conference South side Whitehawk FC. Featuring Edinho Junior, they lost their league opener 3-0 to Maidenhead United.
Stalybridge are at Colwyn Bay this Tuesday, whilst Whitehawk travel to face Bromley.