Jake Guentzel had two goals and an assist, and Bryan Rust had two assists for the Penguins (23-15-7), who are 2-0-1 since losing eight of their previous 10. They lost 5-4 in overtime at Ottawa on Wednesday.
Brady Tkachuk scored, and Cam Talbot made 40 saves for the Senators (20-22-3), who have lost three of four and five of seven.
"The guys, they kept pushing. They tried," Ottawa coach D.J. Smith said. "I thought if you look at the chances, Jarry made some unreal saves. If he's not as hot as he is tonight, we probably get a bunch more."
Rickard Rakell and Jason Zucker scored 43 seconds apart to give Pittsburgh a two-goal lead in the first period.
Rakell put the Penguins ahead 1-0 on a power play at 11:14, scoring from left of the crease on a rebound after Guentzel deflected a point shot from Jeff Petry, who returned from missing 16 games with an upper-body injury.
Zucker scored in a third straight game to make it 2-0 at 11:57 by spinning off Senators defenseman Jacob Bernard-Docker and wrapping a backhand around the left post. Seven of his 13 goals this season have come in the past 11 games.
"It's just fun," Zucker said. "Scoring goals is why you play the game. Winning games, winning Cups, that's the goal around here. For me, I know scoring helps win games."