Cody Anderson added a power-play goal less than four minutes later.
The Soo had taken a 2-0 on a pair of Andrew Holder goals in the second period.
The Hounds tied it early in the third as Dalton Gertsen and Jacob Gillis tallied. Alexander Grizzel and Cory Bussing assisted on Gertsen’s goal. Pat Rogowski drew the assist on the Gillis power-play goal.
The Hounds outshot the Firehawks 42-36.
On Friday night, the Hounds beat the Firehawks 5-4 in a shootout after scoring late in the second period and early in the third to tie it.
Tyler Thirlby cut the Soo lead to 4-3 at 17:11 of the second period and then Premysl Synek’s power-play goal 2:12 into the third period knotted it up.
In the shootout, Bryce Goulah stopped all four Firehawks’ shooters and Scott Luca and Alex Grizzel scored to secure the win.
Goulah made 26 saves through regulation and the overtime period.
Jacob Gillis and Josh Smith also scored for the Hounds.