Penguins No. 1 goalie Marc-Andre Fleury was back in Pittsburgh with his wife expecting their first child.
The Senators, who have battled injuries all season, didn't get any help on the out-of-town scoreboard as Winnipeg defeated the Buffalo Sabres 2-1. The Jets now trail the Senators and New York Rangers by just a single point for eighth in the conference. Both the seventh-place Senators and the eighth-place Rangers do have a game in hand on Winnipeg.
Although there was talk of revenge on Cooke for the Karlsson injury, not much came of it other than his refusal to fight Ottawa's Chris Neil in the opening minutes.
The only rough treatment Cooke received was booing from the fans every time he touched the puck.
The Penguins jumped out to a quick 2-0 lead midway through the first period.
Jeffrey scored his third of the season off a one-timer at 6:15 following a cross-ice pass from Morrow, who then fed Iginla for his 13th of the season at 10:28.
While going behind the net, Morrow made a no-look pass in the opposite direction to Iginla in front as Anderson was moving away from the puck, giving Iginla an open net to shoot at.
Following a penalty-filled opening period, the Senators started the second with fresh ice and nearly a full two minutes of power-play time but were unable to register a single shot on Vokoun, who was playing in his 700th career game and recorded his 300th win.
The win was also the 200th in the NHL for Penguins coach Dan Bylsma.
Notes: Karlsson is back practising with the Senators and could return to the lineup before the end of the regular season. ... The Penguins were first in the NHL with 3.34 goals per game scored heading into Monday. The Senators were second in goals against allowing just 2.09 per game, just slightly more than the Chicago Blackhawks. ... The Penguins (19-0-0) are one of just three teams (N.Y. Rangers, Columbus Blue Jackets) that have not lost a game this season when leading after two periods. ... The Penguins are 22-3 against the seven other Eastern Conference teams currently occupying a playoff position. ... Crosby continues to lead the NHL in scoring despite having played nine fewer games than his closest pursuer. ... Senators defenceman Chris Phillips is one assist shy of 200 for his career.