But some lackadaisical play as the game wore on gave Tampa Bay hope Saturday and the Lightning took full advantage, storming back late in the third period before coming up just short as Ottawa held on for a 5-3 victory.
"Any time you're up 4-0 after the first period the test becomes to see if you can continue to play," Senators coach Paul Maclean said. "I was pleased with how we came out and started the game but as the game wore on it became harder and harder for us to stay playing.
"That's focus and that's intensity. We did enough to stop the momentum from (the Lightning) coming all the way back."
Jakob Silfverberg, Eric Gryba, Guillaume Latendresse and Daniel Alfredsson scored during a 7:01 span of the opening period as Ottawa (17-9-6) jumped out to a 4-0 lead.
Tyler Johnson scored twice in the third period for Tampa Bay (13-17-1) before Teddy Purcell made it 4-3 with just under two minutes to go in regulation.
But with the Lightning pressing for the tie late, Alfredsson added his second of the game into an empty net to seal the Ottawa victory.
"There was something different and we're going to look at it tomorrow, but we didn't play as well as we should," Senators defenceman Sergei Gonchar said of the third period. "But the most important thing this time of the year is that we're getting points as a team."
Robin Lehner made 29 saves to get the win, while Marc Methot, who missed last game with a knee injury, and Kyle Turris each added two assists.
Mathieu Garon was yanked from the Tampa Bay goal during a dismal first period where he stopped just eight of 11 shot. Cedrick Desjardins was strong in relief, making 19 saves the rest of the way.
Lightning coach Guy Boucher was happy with his team's performance outside of final 10 minutes of the first period.
"The rest of the game we played good. We outplayed the other team, out chanced them," Boucher said. "We did a lot of good things out there but the mental mistakes cost us. We played 50 great minutes and that's how we have to play. We can't allow those mental mistakes to happen."
The Senators' barrage started when Silfverberg tipped home a Methot pass after a terrible giveaway by Tampa Bay defenceman Victor Hedman at 12:49 and was followed up just 1:40 later when Gryba scored the first goal of his NHL career off a feed from Turris.
"It feels good and it feels even better to get a big two points," said Gryba, who was playing in his 18th career game. "You play with skill guys like (Turris), they see the ice so well and are able to put the puck where they want it. It was a great pass and I was fortunate to get it past the goalie."
Latendresse scored Ottawa's third goal on a great display of hand-eye co-ordination at 17:01 to chase Garon and Alfredsson made it 4-0 with 10 seconds left in the period on the power play.
Lehner, who was aided by two shots off the post that stayed out, stopped Dana Tyrell on a second-period breakaway as Ottawa started to sit back and allow the Lightning time and space.
Johnson tipped a shot past Lehner at 11:37 of the third and added his second at 13:53 to cut the Ottawa lead to two.
Purcell's goal that made it 4-3 raised the tension at Scotiabank Place, but with Desjardins on the bench for the extra attacker, Alfredsson put the game to bed into the empty net.
Notes: Brian Lee, Marc-Andre Bergeron and Pierre-Cedric Labrie were scratched for the Lightning. Jim O'Brien, Kaspars Daugavins and Andre Benoit sat out for the Senators. ... With his first-period assist, Gonchar set a Senators' club record with assists in 10 straight games. It is also the longest streak in the NHL this season. ... B.J. Crombeen added to his league lead in major penalties with two fights Saturday. He now has 12 major penalties. ... Cory Conacher is fourth in Lightning scoring this year and first among all NHL rookies with 22 points.