Lehkonen's goal came 3:42 after Drouin tied the game 2-2 at 8:32. Smith made the save on shots by Max Domi and Andrew Shaw, but Drouin slid the third over the goal line.
"We knew, everybody knew, we had to come out hard in the third period, and I think we did just that," Lehkonen said. "We got our legs going again and we really put the pressure on in their end and started playing in the offensive zone."
Price, who had one win, a 4.41 goals-against average and an .854 save percentage in his previous five games, made a blocker save on Johnny Gaudreau at 7:33 to keep Montreal within one goal and made the save on Mikael Backlund's redirection from the top of the crease at 9:05 to keep the game tied.
"There's been a lot of goals-against lately, but we put more of that on us than we put on him," Canadiens forward Brendan Gallagher said. "We took a step in the right direction. I think we allowed less prime scoring chances, still a little bit too many. He still made some big saves at big times, which is what he's going to do. He's got his reputation as Carey Price, the best goalie in the world, for a reason, and we have that confidence playing in front of him, and I don't think anyone was ever worried."
Tatar scored with a shot off Smith's glove to put Montreal up 1-0 at 8:00 of the first period. He has five goals in his past five games.
Tkachuk tied it 1-1 with a power-play goal on a one-timer through a screen and past Price's blocker at 3:43 of the second period. He scored his second of the game at 15:53 to put Calgary up 2-1.
