Sidney Crosby ended a two-game pointless streak by assisting on three goals, giving him an NHL-leading 58 points in 34 games and 26 points in December. Crosby, 19, has had only one streak of three games without a point since coming into the league last season.
The Maple Leafs, with former Penguin Jean-Sebastien Aubin in goal, lost here for the first time in eight games since Nov. 1, 2001, mostly because they gave Pittsburgh 10 power-play chances.
The Penguins have scored five power-play goals in two games since breaking out of a 2-for-35 slump with the man advantage.
Or, as in the case of Gonchar's sixth goal, a two-man advantage. With Bryan McCabe and Mats Sundin off after drawing penalties 16 seconds apart, Gonchar blasted a pass from Crosby off Aubin's blocker.
Gonchar's goal came less than a minute into the third period. About six minutes later on another power play, Gonchar faked a slapshot from the point and slid the puck to Evgeni Malkin, who scored his 18th goal of the year.
Erik Christensen had given Pittsburgh a 1-0 lead for the second game in a row, this time in the final minute of the first.
The Maple Leafs, playing without forward Darcy Tucker (bruised foot) lost their fourth in five games despite Mats Sundin's 16th goal midway through the second, the only one of 31 shots to get past goalie Marc-Andre Fleury. Sundin's 36th goal in 47 career games against Pittsburgh was the 512th of his career, tying him with Gil Perreault for 31st place in NHL history.
Toronto had won nine of its last 10 against the Penguins.