Stuart's goal broke a tie a period after brother Colin scored his first NHL goal for Atlanta, and the Bruins ended a six-game skid with a 5-2 victory over the Thrashers on Monday.
"It was nice," Mark Stuart said. "He one-upped me earlier so I had to do it."
Phil Kessel and Matt Lashoff added insurance goals in the third for Boston. P.J. Axelsson also scored for the Bruins, 0-5-1 in their previous six games. It was their worst stretch since they ended last season 0-6-0.
Colin Stuart's first NHL goal came in just his second career game. Bobby Holik also scored for the Thrashers.
"Getting that first NHL goal is exciting, but it would've made it more exciting if we came out of here with a win," Colin Stuart said.
Atlanta led 2-0 after one before Boston scored three in the second.
"I think we stopped trying so hard and stopped doing the easy things and cost ourselves a game," Atlanta goalie Kari Lehtonen said.
With the score tied 2-all, Mark Stuart fired a slap shot from the top of the left circle that got past Lehtonen to move Boston ahead 9:40 into the second period.
"I think we just decided to play," Boston coach Claude Julien said. "That's what my message was to them right after the first period."
Kessel and Lashoff's goals both came on power plays in the opening 6:37 of the third. Boston was 3-for-4 on the power play.
Kessel scored off the rebound of Andrew Ference's shot from the point 2:05 into the final period. Lashoff's slap shot from the left point beat Lehtonen inside the far post.
Lehtonen had shut out Boston 5-0 with 26 saves Saturday night in Atlanta. Thrashers' left wing Ilya Kovalchuk, the NHL's leader with 32 goals, was held to one assist.
Wideman's power-play score cut it to 2-1 at 4:40 of the second period. After Lehtonen lost his stick battling for a loose puck behind the net, Wideman fired a wrist shot from the point that slipped inside the left post.
The Bruins tied it 24 seconds later when Axelsson tipped Zdeno Chara's shot from the point into the air and past Lehtonen.
With Bruins center David Krejci off for holding, the Thrashers moved ahead 1-0 when Holik scored on a power play 9:18 into the game.
The Thrashers made it 2-0 on Colin Stuart's goal. Todd White centered a pass from the right circle and Stuart slipped a wrist shot by Thomas at 13:18.
Lehtonen stopped Marco Sturm on a clean breakaway in the closing seconds of the opening period with a blocker save.
Krejci was called up from Providence on Sunday when C Vladimir Sobotka was sent down. ... The Bruins opened a five-game homestand Monday. They went 1-3-1 in a five-game home stretch before Christmas. ... Kovalchuk had scored at least one goal in seven of his previous 10 games. ... Boos turned to cheers late in the game when the scoreboard flashed a picture of Don Shula before a message congratulating the Patriots on their 16-0 regular season led into highlights of their finale.
Copyright by STATS LLC and The Associated Press
Arena: TD Garden Location: Boston, Massachusetts
Referees: Chris Rooney, Kelly Sutherland Linesmen: Ryan Galloway, Brian Mach
Attendance: 17,565 (100.0% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Bobby Holik (5)
(Power Play) Assists: Ilya Kovalchuk, Tobias Enstrom
Colin Stuart (1)
Assists: Todd White, Steve McCarthy
Dennis Wideman (5)
(Power Play) Assists: Chuck Kobasew, Andrew Ference
P.J. Axelsson (8)
Assist: Zdeno Chara
Mark Stuart (2)
Assists: Peter Schaefer, Glen Metropolit
Phil Kessel (11)
(Power Play) Assists: Andrew Ference, David Krejci
Matt Lashoff (1)
(Power Play) Assists: Zdeno Chara, Marc Savard