"We've played each other so much over the last two years, it doesn't matter who's going good or how the past couple weeks have been going," said Heatley, who had his 16th multi-point game of the year. "Whether they are hot or not, we know it's going to be a tough game."
The Senators certainly made it tough for the Sabres, especially in the second period when they scored three times to take a 3-1 lead into the third. The Sabres tried to claw their way back after Adam Mair cut the Senators' lead to 4-3 with 7:37 left in regulation, but Gerber helped preserve the win with a couple of standout saves while Buffalo was on the power play late in the third.
"They're one of the better teams in the conference, and I think that they think that we are also," Ottawa captain Daniel Alfredsson said. "Both teams can use this as a measuring stick."
Gerber, 5-1 in his last seven appearances and 9-2 on the road this season, was shaken up just four minutes into the game after taking Tim Connolly's slap shot off the mask, but was able to continue. After a scoreless first period, he helped the Senators withstand a 12-shot blitz during the first nine minutes of the second, yielding only Jochen Hecht's goal at 3:12.
"It shook whatever's left of my brain cells," Gerber said.
Brian Campbell also scored for Buffalo, which lost for just the fifth time in the last 18 games.
Sabres goalie Ryan Miller made 19 saves in his ninth straight start.
"It wasn't our best game," Buffalo defenseman Toni Lydman said. "We have the kind of team that can beat them if we're playing our best."
Vermette gave Ottawa a 1-0 lead 1:42 into the middle frame with his seventh goal, but Hecht tied it 90 seconds later with his 13th of the season, banking the puck off Gerber's stick from behind the goal line a foot from the right post.
Redden restored the Senators lead on the power play when he scored his fifth of the year -- and 100th of his NHL career -- at 8:02. Jason Spezza's slap shot from the middle of the ice near the blueline was deflected by Heatley and ricocheted off the left post right to Redden, who deposited the puck into a gaping net.
Fisher made it 3-1 with just under two minutes to go in the second with his 10th. After Miller blocked Chris Neil's driving attempt, Fisher shoveled in the loose puck from just above the crease.
Alfredsson pushed Ottawa's lead to 4-1 just 26 seconds into the third with his 21st, but Campbell made it 4-2 with a power-play goal 3:43 later.
Heatley capped the scoring with an empty-net goal with .5 seconds left in regulation, his team-leading 23rd tally of the season.
"They were up 4-1 and we battled back," said Sabres forward Jason Pominville, who assisted on Hecht's goal. "We had an opportunity at the end with the power play, but we weren't able to score."
- Connolly had two assists after missing the past two games because of an illness.
- The Senators will play six of their next eight at home.
- Buffalo's next home game will be the Winter Classic outdoor game on Jan. 1.
- Buffalo RW Maxim Afinogenov played in his 500th career NHL game.
- Hecht is off to his best goal-scoring start in his nine-year career.
- Ottawa is now 20-2-2 when scoring first.
- Redden became the first defenseman in Senators history to score 100 goals.
- Spezza extended his point streak to eight games, his third streak of eight or more games this season.
- The Senators finished December with an impressive 7-1-1 mark.