Phil Kessel, Nick Bjugstad and Jake Guentzel each had a goal and an assist for the Penguins (39-23-9), who remained two points behind the New York Islanders for second place in the Metropolitan Division.
"The team's been playing awesome, obviously, and then they didn't do anything different tonight," DeSmith said. "They were great again tonight. It was definitely a team shutout, team win."
WATCH: [All Penguins vs. Sabres highlights]
Carter Hutton made 23 saves for the Sabres (30-31-9), who were shut out for the third game in a row and lost a season-high sixth straight game.
"We gave up two power-play goals and a point shot with an unbelievable screen by them," Buffalo forward Jason Pominville said. "That's winning hockey. That's what we've got to get back to. We've got to have more pride to get to that area, get our nose dirty. I mean, it's a tough league to score in. You've got to pay a price to get to the net, and we've got to get pucks there. Right now, we're definitely not doing it enough."