After Friday's 5-1 defeat at New Jersey, Canadiens Coach Michel Therrien said his team played without pride. General Manager Andre Savard took it a step further, holding a closed-door meeting Saturday afternoon.
Montreal responded with a solid defensive effort and avoided a third straight loss.
Theodore, who did not play Friday, defeated the Devils for just the second time in 10 career decisions. The reigning Hart and Vezina Trophy winner took a shutout into the third period and improved to just 2-5-2 since a season-opening victory.
Perreault tallied in the final minute of the second period to give the Canadiens a 2-0 lead and padded it early in the third to complete his third two-goal game of the season.
Donald Audette had the other goal and registered his first point of the campaign for Montreal, which has allowed just two goals in its last three victories.
Defenseman Colin White scored the lone goal for the Devils, who were trying to match a season high with their third straight win.
Benched for four games earlier this month, Audette finally got on the scoresheet 4:01 into the first period off a feed from Saku Koivu.
Perreault got the back-breaker with 41 seconds to go in the second period. Former Devil Doug Gilmour made a no-look, behind-the-back pass and Perreault ripped a one-timer from the left faceoff dot over the left shoulder of goaltender Martin Brodeur.