New Norwegian signing Rune Lange fired Hartlepool ahead on his first start for the club after 36 minutes. Alan Navarro played a blind header towards his own goal that Lange pounced on and finished well.
Gerba responded within 60 seconds to take League One’s top goal scorers – deprived of 12-goal Aaron Wilbraham through suspension – to 59 for the season.
Jemal Johnson raced down the left and sent over a cross that Luke Chadwick miscued, but fortunately Gerba was in the right place at the right time and smashed home.
With the game seemingly heading for a draw, the lively Johnson found space to whip in a centre which full-back Dean Lewington headed in.
And Dons secured the points in stoppage time when Tore Andre Flo unselfishly squared the ball for Gerba to smash into an empty net for his second.