Quarterback Travis Lulay threw one touchdown pass and ran for another, defensive tackle Jermaine Reid had two sacks and Dante Marsh and Adam Bighill had big interception returns as host B.C. shut down Montreal to stay perfect at home.
Lulay found Shawn Gore for a touchdown as part of an 18-for-22, 198-yard first-half performance for the Lions (7-4), who improved to 6-0 at B.C. Place.
Marsh's 39-yard interception return set up Lulay's touchdown run and Bighill returned an interception 44 yards to set up a 1-yard TD by running back Andrew Harris, who finished with 68 rushing yards.
Quarterback Tanner Marsh was replaced by Josh Neiswander after Marsh was 9-for-17 for 76 yards in two-and-a-half quarters for the Alouettes (4-7), who have lost two straight.
Neiswander, who finished 14-for-23 passing for 153 yards, found slotback S.J. Green and wide receiver Brandon London for touchdowns but also threw two interceptions.
Momentum appeared to be shifting after Neiswander's 2-yard toss to Green pulled the Alouettes within eight points with 3:13 remaining in the third quarter. Montreal got the ball back less than two minutes later, but Bighill picked off Neiswander on the second play of the following drive and Harris closed out the quarter with his score.
Lulay completed 1-of-6 passes and threw two interceptions in the second half before rushing 14 yards for a touchdown with 8:43 remaining.
Neiswander connected with London for 35 yards 1:40 later, but the Alouettes could not get any closer as Lions backup quarterback Thomas DeMarco found Marco Iannuzzi for a 14-yard touchdown with 2:34 remaining.
NOTEBOOK: The Lions have won 12 straight at home and haven't lost since a 27-14 setback to Edmonton on July 20, 2012 ... Montreal LB Mike Edem led the team with seven tackles and one interception, while linebacker Chip Cox and defensive end Aaron Lavarias each had sacks ... The Alouettes defeated BC 39-38 in Montreal in Week 9 ... Lions SB Courtney Taylor led all players with 117 receiving yards.