John Mitchell's team took a narrow 15-10 advantage into the half-time break but ran in four second-half tries to ensure they will be full of confidence ahead of their season opener against the Sharks in Durban next Friday.
James Stannard and David Pusey both crossed the whitewash in the opening period to give the hosts the lead after Reds full-back Chris Latham had scored the game's opening try.
Cameron Shepherd touched down soon after the interval and a runaway intercept try from Drew Mitchell extended the Force's advantage, before Chris Siale's unconverted effort brought his side to within touching distance after 60 minutes.
But from there it was all the home side as they took full advantage of Reds lock James Horwill's sin-binning to score further tries from Nick Cummins and Lachlan McKay.
The Reds open their Super 14 at home to the Highlanders in Brisbane next Friday.