Marc-Andre Fleury made 20 saves and Alexei Ponikarovsky and Bill Guerin also scored for the defending Stanley Cup champion Penguins, who won their second in a row following a 5-4 loss to the Senators in the series opener.
Mike Fisher and Matt Cullen scored power-play goals for Ottawa. Brian Elliott stopped 20 shots.
Game 4 is Tuesday night in Ottawa.
Malkin restored Pittsburgh's one-goal lead at 2-1 in the second not long after Fisher drew the Senators even with a power-play goal 1:53 into the period.
The 2009 Conn Smythe Trophy winner as the playoff MVP, Malkin jumped on a loose puck beside Elliott and fired into an open net at 5:57 after the Ottawa goalie failed to poke it away.
Max Talbot drew an assist on the play, pushing the puck away from rookie Senators defenseman Erik Karlsson as the two raced toward the goal to recover the puck after it got away from Malkin on a rush into the Senators' zone.
Crosby, who had five points in the first two games in Pittsburgh, made it a 3-1 with 44.4 seconds left in the second. The Penguins' 22-year-old captain carried the puck across the goalmouth from the right corner, holding onto it before putting a shot over a sprawled Elliott for his first power-play goal of the playoffs.
Crosby added his seventh point, his fifth assist, when Guerin's breakaway goal increased the lead to three 4:27 into the third.
Fisher gave the Senators' fans some hope when he converted Ottawa's first power-play opportunity early in the second to tie it at 1. Cullen's goal at 12:58 of the third also came with the man advantage, though it only drew the Senators within two.
Ponikarovsky quieted the Scotiabank Place crowd with his first goal 1:17 in. The former Toronto Maple Leafs left wing carried the puck along the right side before stopping in the faceoff circle, holding off for a moment while Karlsson passed him along the ice before firing a wrist shot past Elliott.
The Senators thought they had scored the tying goal with 40.8 seconds remaining in the first. After a video review, referee Eric Furlatt waved his arms and announced, "The puck was kicked in — no goal," to the dismay of the crowd. Repeated replays had already shown Peter Regin kicking the puck with his right skate between Fleury's pads after Jason Spezza's centering pass from behind the net landed at his feet.
Notes
G Brad Thiessen backed up Fleury for the second game in a row. … Penguins D Jordan Leopold did not travel to Ottawa. Leopold is day-to-day after he was knocked out of Friday night's game on a hit by Senators D Andy Sutton. Veteran D Jay McKee replaced Leopold in the lineup.