"I think it's discipline. You have to be responsible for your actions with your stick," Ottawa coach John Paddock said.
"It wasn't a great effort for us," Ottawa's Chris Kelly said. "I think the score might have been a lot worse if not for Gerber. He kept us in the game."
The Senators took a 2-1 lead with three minutes left in the second period on a goal by Daniel Alfredsson, his 20th. He beat Lehtonen with a shot that went between the goalie's legs. Jason Spezza, who scored Ottawa's first goal, assisted with Dany Heatley.
The Thrashers tied it 46 seconds later when Ilya Kovalchuk put a rebound of Ken Klee's shot past Gerber. It was the NHL-leading 28th goal for Kovalchuk, who has scored four times in three games.
The Senators took a 1-0 lead in the first period on Spezza's 11th goal, converting a perfect cross-ice pass from Randy Robitaille at 5:43.
Atlanta tied it at 1 at 7:14 of the second period when Eric Boulton scored his third goal.
The Thrashers outshot Ottawa 21-7 in the first period, but trailed 1-0. ... Atlanta matched the 45 shots they recorded on Jan. 18 against Montreal. ... Ottawa outscored the Thrashers 19-11 this season. Kovalchuk scored seven of Atlanta's goals. ... Heatley has six goals and three assists in his last five games and 12 goals and 10 assists in 15. ... Alfredsson extended his point streak to 10 games (four goals, 11 assists). ... Recchi has two goals and three assists in five games since being claimed off waivers from Pittsburgh.
Copyright by STATS LLC and The Associated Press
Arena: Philips Arena Location: Atlanta, Georgia
Referees: Kerry Fraser, Dan O'Rourke Linesmen: Brian Mach, Andy McElman
Attendance: 14,085 (76.0% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Jason Spezza (11)
Assist: Randy Robitaille
Eric Boulton (3)
Assists: Chris Thorburn, Jim Slater
Daniel Alfredsson (20)
Assists: Jason Spezza, Dany Heatley
Ilya Kovalchuk (28)
Assists: Ken Klee, Bobby Holik
Todd White (9)
(Power Play) Assists: Tobias Enstrom, Mark Recchi