MONTREAL -- With a sold-out home crowd braced for the possibility of witnessing Montreal's worst start in nearly 70 years, a couple of newcomers gave Canadiens' fans an opportunity to celebrate a victory.
Gionta, who also scored late in the first period, sealed the win with a backhander past Ondrej Pavelec on Montreal's third attempt of the shootout.
"It's every little kid's dream," said Gionta, who left the New Jersey Devils as a free agent to sign a five-year, $25 million contract with the Canadiens on July 1. "You've got 22,000 people screaming and you're in the spotlight. Those are the things you love as a player."
Gomez had put a shot from the slot past the Atlanta goalie's glove into the right side of the net.
"It's not a good feeling when you come back to the bench and your teammates are surprised that you have a shot like that," said Gomez, acquired from the New York Rangers on June 30. "It kind of hurts your feelings a little bit. I got a little lucky, I don't know if I could do that again, but I'll take it."
Atlanta's Vyacheslav Kozlov got a boarding major and a game misconduct for his check from behind on Gomez 2:25 into overtime.
"I won't give him the satisfaction," Gomez said when asked to comment about the hit. "We got the two points so I could care less what happens."
The Canadiens (3-5) avoided their worst start since 1940, when they were 1-10-1. Montreal was 2-5-1 in 1956 and 1980.
"I thought it was big," Gionta said. "We showed a lot of staying power there. When you lose five in a row and a team ties it up in the third period like that it could kill your confidence, but I thought we did a good job of sticking with it."
Colby Armstrong brought Atlanta into a 1-1 tie at 6:06 of the third with his first goal. Armstrong took Peverley's pass from the left corner and put a wrist shot past Halak from the circle.
"Our line played really well," Armstrong said. "The guys were hard on the puck and we really were attacking. It was just a matter of burying a chance. We'd talked about that soft spot there all night long and a couple of cycles and we got it there and it just happened to work out well and I just got a little screen shot off."
Halak made 22 saves in his second start of the season.
"He did a great job," Gionta said. "When you're not playing a lot of games and you come in like that, he showed a great effort. He was strong back there. He made big saves for us and that's what you need."
Pavelec stopped 34 shots for Atlanta (4-1-1), which tied its best start since joining the NHL in 1999.
"He played really, really well, and I thought their goalie played really well, too," Thrashers coach John Anderson said. "He made some big saves for them, too, and you don't get goaltending battles like this very often and it was great. I was very, very happy with it and I wish we would have won at the end, but that's the way it goes."
Montreal, which won its first two games of the season in overtime, has been held to 10 goals in its last six contests.
Dating to a 6-2 win at Toronto on April 4, the Canadiens have not won in regulation through 16 games, including their four-game loss to Boston in the opening round of last season's playoffs.
Peverley, who has eight points in six games, signed a multiyear contract extension earlier in the day. The 27-year-old center has four goals and four assists and leads the Thrashers with three power-play goals and two winning tallies.
The Canadiens held a 35-23 shots advantage, including 13-6 in the second and 7-0 in overtime. Canadiens coach Jacques Martin used his timeout with 1:15 remaining in the extra period.
Gionta opened the scoring with 2:16 left in the first when he beat Pavelec with a wrist shot from the left side.
The Thrashers also started 4-1-1 in 2006. ... Peverley has 43 points in 45 games with Atlanta since he was claimed off waivers from Nashville in January. ... D Marc-Andre Bergeron made his Montreal debut. Bergeron, recalled from AHL Hamilton on Sunday, was called for hooking on his first shift. ... Carey Price's next appearance will be his 100th NHL game. The Canadiens' 22-year-old goalie is 2-4 in six starts this season with a 3.36 goals-against-average and a .886 save percentage.