Kris Letang, Paul Martin and Matt Cooke also scored, Sidney Crosby had three assists, and Tomas Vokoun made 21 saves against his former team for the Penguins (6-3), who have won three straight and four of five to lead the Atlantic Division.
Mike Green, Carlson and Mike Ribeiro scored for the Capitals — and Carlson's goal was an accident that took a weird carom off a stanchion along the glass.
Two-time league MVP Alex Ovechkin, who said before the game that he was somewhat embarrassed to have only three points on the season, contributed a secondary assist on a third-period power-play goal with Washington (2-6-1) trailing by three.
PANTHERS 4, SABRES 3
BUFFALO, N.Y. (AP) — Defenceman Brian Campbell scored on the power play with 10:33 remaining to cap Florida's three-goal rally and the Panthers beat Buffalo.
Peter Mueller, George Parros and Shawn Matthias also scored for the Panthers, who won their first road game of the season and snapped a seven-game road winless drought (0-5-2) dating to last season. Florida (3-5) rallied from a 3-1 deficit to win two straight since enduring a five-game skid.
Thomas Vanek and Cody Hodgson had a goal and assist each, and Alexander Sulzer also scored for Buffalo, which dropped to 1-5-1 since opening the season with two wins.
The Sabres were playing their third game in four days.
DEVILS 2, ISLANDERS 0
UNIONDALE, N.Y. (AP) — Johan Hedberg made 22 saves for his 22nd career shutout, leading New Jersey to a win over the Islanders.
Steve Bernier scored for New Jersey in the third period and David Clarkson added an empty-netter to help the Devils snap a four-game winless streak (0-1-3).
New York (4-3-1) outshot the Devils 10-7 in a high-tempo first period, while New Jersey (4-1-3) implemented its trademark defensive system in the second.
Hedberg's biggest save came 8:08 into the third period when he stoned New York right wing Michael Grabner on a short-handed breakaway with the game scoreless.
CANADIENS 2, SENATORS 1
MONTREAL (AP) — David Desharnais and Erik Cole scored first-period goals and Montreal held on for a victory over Ottawa.
The win completed a sweep of weekend matinees at home for Montreal (6-2-0) after a 6-1 win Saturday over the Buffalo Sabres. The Canadiens have won five straight at home after dropping their home opener to Toronto on Jan. 19.
Jakob Silfverberg scored for Ottawa (5-3-1), which was coming off a 1-0 loss at Carolina on Friday night. Senators goalie Craig Anderson has not conceded a goal after the first period in eight games this season.