Erik Christensen also put the puck past Montreal's David Aebischer for the Penguins, who won their second shootout in a row - they beat Dallas 4-3 on Friday - after losing five of their first six.
Montreal lost its fifth in nine shootouts as Penguins goalie Marc-Andre Fleury stopped the final two Canadiens shooters, Chris Higgins and Tomas Plekanec, after Alex Kovalev had matched Christensen's goal.
The Canadiens trailed 4-2 after Sergei Gonchar scored twice during a seven-minute Pittsburgh power play in the second period and Malkin tipped in another slap shot by Gonchar on another power play. But Montreal tied it on goals by Mike Johnson and Mathieu Dandenault in the final 5½ minutes of the third.
Johnson scored Montreal's second short-handed goal of the game - Radek Bonk also got one - and NHL-leading 15th this season. Dandenault scored the tying goal, only his second of the season, when he fired the puck toward the net from the right circle and it deflected off defenceman Rob Scuderi's skate and past Fleury with 2:21 left in the third.