Rookie Jean-Gabriel Pageau scored his first three career playoff goals, and the Ottawa Senators pounded the Montreal Canadiens, 6-1, in a spirited Game 3 at Scotiabank Place.
"Great night for the kid. He's come in and played very, very well for us," Ottawa head coach Paul MacLean said about Pageau.
Daniel Alfredsson had a goal and two assists for the seventh-seeded Senators, who grabbed a 2-1 lead in this Eastern Conference quarterfinal series.
Erik Karlsson and Sergei Gonchar each had two helpers in the lopsided win, while Craig Anderson made 33 saves.
Carey Price surrendered all six Ottawa goals on 30 shots.
The Senators will look to put the Northeast Division winners in an even deeper hole when they host Game 4 on Tuesday.
The teams combined for 236 penalty minutes, the majority coming in a fight- filled third period during which the Senators scored four goals.
Pageau gave the Senators a 3-1 lead 1:18 into final frame. He used a Montreal player as a screen and snapped a wrister from the top of the left circle high over Price's glove.
Kyle Turris found the back of the net at the seven-minute mark, and Jakob Silfverberg made it a 5-1 game eight seconds later.
A melee broke out between the two tallies, with all 10 skaters on the ice being assessed fighting majors at 7:04. Montreal center Ryan White incited the fracas with a slash on Zack Smith, and Silfverberg scored after a faceoff win on the ensuing power play.
Pageau completed the hat trick on another man advantage with 1:58 remaining.
"After we made a couple mistakes and got down, I think we didn't respond the right way," said Montreal defenseman Josh Gorges. "In the playoffs, (at) this time of year, we can't lose our cool, and I thought for a stretch there in the third we lost our heads."
The teams traded power-play goals in the opening period.
Ottawa drew first blood on a 5-on-3 advantage after working the puck high to low. Gonchar spotted a seam and the veteran defenseman threaded a pass to Alfredsson at the left side of the net. The Senators captain played the puck off his skate and slipped it under Price at 5:58.
Rene Bourque answered for Montreal, taking a feed from Tomas Plekanec and firing a shot from the slot past Anderson at 14:34. The shot grazed Anderson's right pad as he dropped to his knees, but the puck still had enough momentum to crawl across the goal line.
Pageau snapped a 1-1 tie at 4:40 of the middle stanza. A darting Pageau beat Price on the stick side from between the circles after Gonchar hit him in stride with a pass through the neutral zone.
The Ottawa forward was clipped in the face by the stick of Montreal defenseman P.K. Subban when he released the shot, but the Canadiens were able to kill off the penalty.
Ottawa defenseman Patrick Wiercioch suffered a lower-body injury in the first period and did not return ... The Senators were 3-for-10 on the power play ... Forwards Brian Gionta and Max Pacioretty both returned to the Montreal lineup after sitting out Game 2 with upper-body injuries.