Teenager Lewis Bunker had been forced out earlier after suffering a puncture and "Herc" Thomson was also a withdrawal.
Back at the front of the race, the Bushy Park climb saw Cameron and McNeill struggle, while the remaining four stayed together until part-way up Otakina Hill on the return leg, when Scrimshaw and Forrester attacked and opened a gap.
With their companions dropped and the back-markers too far behind to present a real threat, Forrester and Scrimshaw appeared to have the race to themselves.
However things changed at 5km to go with the reappearance of Shaun Tucker, who had put in a Herculean effort to rejoin the breakaway duo.
From there it was a dogfight Tucker constantly putting in aggressive attacks without being able to get rid of his rivals.
In the charge to the line Tucker went early but ran out of steam and was overhauled by Forrester, who then had to withstand the late challenge from Scrimshaw to gain the narrowest of wins.
It was a well-earned victory by Forrester, who has had a fruitful late-summer campaign and ridden far better on hillier courses than he had in recent years.
Tucker boxed on well for his third placing ahead of Gemmell, who rallied well for fourth.
Goode roared into fifth, clocking the day's fastest time (1:24.21) just ahead of his fellow scratch man Bismark.
A small field of C-grade riders combined to race around one lap of Western Line, then out to the top of Okatina Hill and back.
Comeback rider Steve Carle and Michaela Walker did a lot of strong work early on and pulled away from their rivals in the latter stages.
Carle then called on his experience to out-finish his much younger companion to take the win Walker nailing down second from Debbie Cain in third and Jim Callaghan fourth.
Results
A & B Grade: 1. Darcy Forrester; 2. Brian Scrimshaw; 3. Shaun Tucker. Fastest time: Matt Goode (1:24.21).
B & C Grade: 1. Steve Carle; 2. Michaela Walker; 3. Debbie Cain.