"I'm feeling young," said the 29-year-old Fisher, who was teamed with 36-year-old linemates Kovalev and Daniel Alfredsson. "They create so much space, they both make great plays and they're strong on the puck. They made some great plays tonight -- we could have had a few more."
Kovalev scored his first Senators goal 43 seconds in, and Jarkko Ruutu added Ottawa's second goal 1:42 later to open up a 2-0 lead 2:25 into the game.
"It feels great to get my first goal but to get the win, that's the most important thing," said Kovalev, who has 395 career goals, including over 100 each with the New York Rangers, Pittsburgh and Montreal. "When you score goals and don't get the win, that's frustrating."
"I don't think we showed up for this game," Kovalchuk said. "I don't know whether we were ready at the start and then they capitalized on us and scored a couple of quick goals. We came back and in the second period we had a couple of chances to take the lead, but their goalie played well. That goal on the power play made the game."
Pavelec made his third straight start and stopped 30 shots.
Vyacheslav Kozlov appeared to have drawn Atlanta (2-1-0) within one midway through the third, but the goal was immediately waved off. A video review supported the referee's ruling that Kozlov had deflected the puck with a high stick.
"We just tried to beat everybody by ourselves, but we just need to play like a unit, like we did the first two games," Kovalchuk said.
Chris Phillips drew a roughing minor at 13:27 as a number of Senators came to Alfredsson's defense after Bogosian knocked the Ottawa captain to the ice in the neutral zone.
Kovalev, who left the Canadiens to sign a two-year, $10 million deal with Ottawa, got his first goal in four games with a shot into a gaping net 43 seconds in.
Ruutu got his first of the season at 2:25 to make it 2-0.
Kovalchuk has 12 goals and six assists overall in 14 games at Scotiabank Place. ... Senators C Peter Regin left the game midway through the third with an upper body injury. He did not return.