Sidney Crosby had a goal and two assists, Kris Letang had three assists and Matt Murray made 30 saves in his fifth straight win since returning from injury for the Penguins (20-12-6), who have won seven of their past eight games. Phil Kessel had three assists.
"I think tonight it wasn't necessarily a 6-1 game," said Crosby, who has nine points (one goal, eight assists) in his past three games. "I think Murray made some big saves and allowed us to capitalize on the chances we got. The power play was good. I still think we can build in certain areas. We're confident because we found ways to win, but we still feel like we can improve in some areas too."
WATCH: [All Penguins vs. Blues highlights]
David Perron scored and Jake Allen was pulled in the second period after allowing four goals on 17 shots for St. Louis (15-17-4). Jordan Binnington made 11 saves in relief.
The Blues penalty kill has allowed 11 power-play goals in six of the past seven games, including all four of Pittsburgh's chances.
"They got one early, but what did they score, four power-play goals?" said St. Louis captain Alex Pietrangelo, who returned after missing the previous 11 games with a broken right hand. "Penalty kill wasn't good enough. They don't get those chances, you do the math; it's 2-1, a much closer game. Tough to give those guys that many opportunities."
Crosby scored a power-play goal 48 seconds into the game to give the Penguins a 1-0 lead after Alexander Steen took a high sticking penalty nine seconds after the opening face-off.
"We gave them opportunities on the power play and they capitalized on all of them," Steen said. "The first two were on me, puts us in a hole from the start of the game. ... I have to find a way to keep the stick down."
The Penguins scored three goals in 4:12 during the second period. Juuso Riikola's first NHL goal made it 2-0 with Pittsburgh's second power-play goal at 5:13, Zach Aston-Reese made it 3-0 at 7:17, and Patric Hornqvist scored a power-play goal to make it 4-0 at 9:25.
