Jimmy Howard made 34 saves as Grand Rapids took a 3-2 lead in the North Division final series with a 3-2 victory over host Manitoba on Saturday night.
The teams head back to Grand Rapids for Game 6 on Monday night and Game 7, if necessary, on Tuesday.
Nate DiCasmirro and Darryl Bootland gave the Griffins a 2-0 lead just 4:36 into the game, and Jiri Hudler made it a three-goal cushion early in the second period.
Craig Darby and Rick Rypien scored in the third for the Moose but they could not complete the comeback, despite a 30-8 edge in shots on goal over the final two periods of play.
Valtteri Filppula dished out a pair of assists for Grand Rapids, which improved to 5-1 on the road this postseason.
Attendance at the MTS Centre was 9,185.