BOSTON -- The Boston power play finally clicked on Saturday night as the Bruins defeated Montreal 4-2 to leave the Canadiens on the edge of a playoff precipice.

After a five-year post-season drought with the man advantage against the Habs, Boston broke the power-play hoodoo when Reilly Smith and Jarome Iginla scored 32 seconds apart early in the second period to pull ahead 3-0. Tomas Plekanec was in the penalty box for both goals.

"I thought we were intent when we started the game but their power play gave them a lot of momentum and confidence," said Montreal coach Michel Therrien.

Boston was 0-for-10 in the series on the power play and amazingly had not scored in 39 tries with the man advantage against Montreal in the post-season since Game 2 of their 2009 Conference quarter-final.

A late P.K. Subban goal made the score closer than the game actually was.

Game 6 of the second-round playoff series is Monday in Montreal with the Canadiens needing a win to remain alive -- undoubtedly regretting the Game 4 overtime loss at the Bell Centre that rejuvenated the Bruins.

Game 7, if needed is next Wednesday in Boston.

Carl Soderberg and Loui Eriksson also scored for the Bruins, who got a strong physical game from Milan Lucic. The hulking winger cruised the ice like a shark, looking for someone to take a piece out of.

The line of Soderberg, Eriksson and Matt Fraser finished with two goals and three assist and was plus-six. The Bruins third line has now scored three of Boston's last five goals with Fraser accounting for the overtime winner last Thursday in Montreal.

Brendan Gallagher also scored for the Canadiens, whose power play was 2-for-5 on the night.

The capacity crowd of 17,565 at TD Garden had plenty to cheer about. Bruins coach Claude Julien had said there was more in the Bruins' tank and they showed it Saturday.

Boston had plenty of jump and looked to take the body. Plus the Bruins managed to plug up Montreal's shooting lanes.

Smith hit the post before either team registered a shot. And both teams found themselves killing penalties as five minors -- the total called in the last two games -- were whistled in the first 7:58.

The Bruins looked crisp from the get-go and went ahead on a Soderberg shot after Eriksson beat the lumbering Douglas Murray to the puck behind the net and sent it straight back to his centre, who beat Carey Price at 13:20 for his first career playoff goal. It came on Boston's sixth shot of the night.

It was a good omen for the Bruins, given the team scoring first won the first four games of the series and the Bruins were 5-0 in the playoffs -- and 41-6-2 during the regular season -- with the first goal.

Montreal had been dangerous on the power play earlier in the series but was 0-for-3 with the man advantage in the first period, stymied by an aggressive Bruins penalty killing unit that played close attention to Subban at the point.

Montreal outshot Boston 9-8 in a period that saw four penalties to each team. The Bruins squandered three more chances with the extra man in the first period.

Then came the power play breakthrough as the Bruins dominated the second period.

After some good puck movement had the Canadiens running around, a Dougie Hamilton shot from the point deflected in off Smith's foot. Then, after a Bruins faceoff win, a nifty Torey Krug pass from the wall found Iginla all alone and he snapped a shot past Price.

Boston was bossing the game and the Habs began to lose some of their composure.

But Plekanec made up for some of that time in the penalty box when he snapped a shot from the faceoff dot that went through a Boston defenceman's legs before rattling in off Gallagher at 14:39 on the power play to cut the lead to 3-1.

The five-foot-nine Gallagher got thumped in the corner seconds before on the play, but picked himself up and got in front of the goal to be in position to tip the puck in.

The goal ended Tuukka Rask's shutout streak of 122 minutes six seconds.

Boston led the shot clock 21-20 after two periods.

The Bruins kept up the pressure in the third, coming at the Canadiens. Boston calmly blunted Montreal attacks and then moved the puck up ice with speed and purpose.

Eriksson's goal, with 5:48 remaining, came on a three-on-two complete with some slick passing. Price made the save but was powerless to stop Eriksson, who skated around him until he had a clear shot at an empty net.

With Matt Bartkowski off for holding and Price on the bench, Subban scored from the point to make it 4-2 with 2:29 remaining.

Montreal coach Michel Therrien brought back Brandon Prust, who had sat out the last two games. Making way was veteran Daniel Briere who had played under 10 minutes each of the last three contests.

NOTES -- Thirteen members of the current Bruins squad remain from the team that won the Cup in 2011 ... Bobby Orr and Derek Sanderson were both in attendance on the 44th anniversary of Orr's iconic fly-through-the-air Cup-winning goal, set up by Sanderson.