Thomas denied Rene Bourque on the forehand, robbed Max Pacioretty with a sprawling pad save at the right post and denied Lars Eller with a paddle to stay perfect in shootouts this season at 5-0.
After David Krejci beat Carey Price with a forehand only to hit the post, Seguin scored the only goal in the shootout when he came in slow, paused slightly in the slot and ripped a wrister in from between the circles.
It was a far from perfect performance as the Bruins squandered a two-goal lead in the third period, but they got the win in the end and two very big points to start their six-game road trip off on a winning note. They stay north of the border when they visit Winnipeg on Friday.
End Overtime, 3-3: This one will be settled in a shootout. The bruins had the bulk of the chances in overtime, but Montreal had an offensive-zone faceoff in the closing seconds and Gregory Campbell had to go down to block a Tomas Kaberle shot to end that final threat.
Overtime, 2:39, 3-3: The Bruins inches away from victory again as Brad Marchand breaks in alone down the right wing and beats Price cleanly, only to clang it off the crossbar.
Overtime, 1:29, 3-3: Andrew Ference nearly has another one again, but his shot from the left circle off a nice rush by Chris Kelly is denied by Price flashing out the glove for the save.
Overtime, 1:02, 3-3: The Habs survive a scramble in front on the power play and the ensuing shift with Price playing without a stick until he can tie up the puck for a faceoff.
Overtime, 0:00, 3-3: The extra frame is under way, with the Bruins now on a 4-on-3 power play for the first 37 seconds of the sudden-death period.
End Regulation, 3-3: This one will go to overtime. the Bruins squandered a two-goal lead in the third, but they'll get at least one point and have 37 seconds left of power-play time to start the extra frame to try for the second.
Third Period, 18:37, 3-3: The Bruins will get a late power-play chance as Tomas Plekanec is called for delay of game for sending the puck out of play over the glass.
Third Period, 14:23, 3-3: The Bruins finally with a chance, but Andrew Ference hits the post bidding for his second goal of the night.
Third Period, 13:38, 3-3: The Canadiens continue to pour it on, and only some big saves by Thomas has kept the Habs from taking the lead. The Bruins still do not have a shot in this period, with Montreal outshooting them 9-0 in the frame.
Third Period, 11:12, 3-3: The Canadiens pull even as Erik Cole takes advantage of a brutal giveaway by Zdeno Chara in front of the Boston net.
Cole stole the puck between the circles and broke in alone, beating Thomas with a backhander at the right post.
Third Period, 9:45, Bruins 3-2: The Bruins finally got a couple shifts in the Montreal end to relieve the pressure, first with Daniel Paille creating some chances in deep, then with the Kelly line following up.
Third Period, 7:00, Bruins 3-2: The Canadiens did everything but score early in that power play with plenty of pressure and a wild scramble in front, but the Bruins survive and are back at even strength.
Boston is on its heels though, and desperately need a strong shift in the Habs zone to slow Montreal's momentum.
Third Period, 5:00, Bruins 3-2: The Canadiens now have a power-play chance to tie it as Johnny Boychuk is called for interference.
Third Period, 3:34, Bruins 3-2: The Habs pull within a goal as Max Pacioretty scores.
David Desharnais fed it out to Pacioretty for a one-timer from the high slot as Erik Cole drove the net.
Third Period, 2:00, Bruins 3-1: The Bruins are able to kill off that penalty as Marchand returns to the ice to put the sides back at even strength. That was a huge kill for the Bruins as they try to maintain this lead and not let Montreal back into this one.
Third Period, 0:00, Bruins 3-1: The final frame is under way, and the Bruins open shorthanded with Marchand in the box for clipping.
Second Intermission Notes: The Bruins coughed up their lead early in the second, but bounced back with two more goals to take a 3-1 lead into the third.
The Bruins are usually a sure bet to win when leading after two (22-0-0), but Brad Marchand complicated things a bit with a clipping penalty at the end of the second. Boston needs to kill that penalty off to start the period and prevent Montreal from getting any life.
The Habs have surprisingly more than matched the Bruins' physical play in this one. Montreal has a 19-11 edge in hits and Ryan White more than held his own in the game's lone scrap. His presence in his season debut has made a huge impact, seemingly make the rest of the Habs feel a little bigger in staring down the usually intimidating Bruins.
End Second Period, Bruins 3-1: The middle frame comes to a close, but not before Brad Marchand takes a penalty as the period ends with a low hit on Alexei Emelin that is called clipping. Not a smart play by Marchand, who was suspended for five games for clipping Vancouver's Sami Salo last month.
Second Period, 14:33, Bruins 3-1: The Bruins convert that power play on another pretty goal, this one off the stick of Patrice Bergeron.
Tyler Seguin got the puck down low to Bergeron along the goal line on the left side. Bergeron waited for Price to go down and then roofed it for the goal with six seconds left on the man advantage.
Second Period, 12:39, Bruins 2-1: And yet another goalie interference call gives the Bruins a 4-on-3 power play as Erik Cole now goes for bowling over Thomas in the crease.
Second Period, 11:52, Bruins 2-1: Interesting set of matching penalties as both teams are called for goalie interference at opposite ends of the ice.
Louis LeBlance got the first call for bumping Thomas, but Daniel Paille evened it up on the delayed call as he nudged Price at the other end.
Second Period, 7:27, Bruins 2-1: The Bruins can't convert that power-play chance as the sides are back at even strength.
Second Period, 5:27, Bruins 2-1: The Bruins now go back on the power play as Andrei Kostitsyn goes off for interference.
Second Period, 5:07, Bruins 2-1: The Bruins answer back as Benoit Pouliot scores a highlight-reel tally against his old team.
Pouliot came down the middle, slipped the puck through Chris Campoli's legs and ripped a wrister in from the slot.
Second Period, 1:39, 1-1: The Habs kill the Bruins momentum and tie the game as Mathieu Darche scores shorthanded.
After a Krejci turnover, P.K. Subban carried the puck down the right wing deep into the Bruins zone and centered it to Darche, who put it in around Thomas from the top of the crease.
Second Period, 0:00, Bruins 1-0: The middle frame is under way and both Chara and Krejci are back on the bench after being stitched up. That's a very good sign as Chara in particular looked like he could have been seriously hurt.
First Intermission Notes: The bruins put together a solid opening frame and were rewarded with a 1-0 lead after 20 minutes, but that could be overshadowed if Zdeno Chara's injury proves serious.
Chara was struck in the head by a puck in the closing seconds as Tomas Plekanec cleared it out of the Montreal zone on the penalty kill. The Bruins will begin the second period with just under two minutes left on the power play after Lars Eller cut David Krejci with a high stick for a double minor.
The Bruins lead 12-5 in shots. More importantly, the Bruins have no missed shots after 15 against the Rangers and just five attempts blocked. Nine of those shots have come from defensemen, including three by Ference, who has the game's only goal.
End First Period, Bruins 1-0: The Bruins will head to the first intermission with a 1-0 lead, but there was bad news as well as Zdeno Chara took a puck up high in the closing seconds when struck by a Tomas Plekanec clearing attempt. Chara got up on his own power, but was in obvious pain and bleeding.
First Period, 17:59, Bruins 1-0: The Bruins will get a longer power play after all, as Lars Eller gets a high-sticking double minor after cutting David Krejci with his stick. Krejci goes to the room for repairs while the Bruins go on a four-minute power play.
First Period, 17:09, Bruins 1-0: The Bruins open the scoring as Andrew Ference scores during the 4 on 4.
Brad Marchand forced a turnover behind the net by Hal Gill, and the puck slid to Ference at the top of the right circle for the blast that beat Price short-side.
First Period, 15:43, 0-0: The Habs even that call up as Max Pacioretty is called for goalie interference as the Canadiens can't convert a chance in front, then compound the problem by taking a penalty. It will be 4 on 4 before a brief Boston power play.
First Period, 15:16, 0-0: The Bruins have another key early penalty to kill as Seidenberg goes back to the box again, this time for tripping.
First Period, 14:15, 0-0: The gloves come off as Adam McQuaid and Ryan White exchange words, then punches after the whistle. Both men landed some big blows in a pretty even scrap. McQuaid lost his sweater during the bout but doesn't get game misconduct as it was originally tied down. Just five each for fighting.
First Period, 11:11, 0-0: The Bruins are able to kill off that penalty, something they couldn't do against Rangers, who turned the momentum of Tuesday's game by converting their first power-play chance.
First Period, 9:11, 0-0: The Habs will get the first power-play opportunity of the night as Dennis Seidenberg is called for cross-checking. Montreal got its first shot of the night during the delayed penalty, as Boston leads 5-1 in that category.
First Period, 6:24, 0-0: Shawn Thornton takes a big hit into boards from Alexei Emelin. Thornton appeared shaken up a bit, but got back up to finish shift.
First Period, 3:38, 0-0: The Bruins getting the defense involved in the attack early. Johnny Boychuk pinched in deep for a hit to keep one possession alive, then Chara and Boychuk each launched big shots from the points.
Boston needs more traffic in front though, as Price had clear looks at both and made the saves without difficulty.
First Period, 1:36, 0-0: The Bruins give away the puck at the blue line as Milan Lucic's clear is picked off by Ryan White, but White's shot from the high slot is deflected into the netting. The Bruins can't afford to be sloppy like that if they're going to get back on track in this one.
First Period, 0:00, 0-0: The Bruins' longest road trip of the season is under way as Boston visits Montreal for the final clash between the rivals this season.
7:30 p.m.: The Bruins will start with Patrice Bergeron up front between Brad Marchand and Tyler Seguin, with Zdeno Chara and Dennis Seidenberg together on defense and Tim Thomas in goal.
The Canadiens counter with Erik Cole, David Desharnais and Max Pacioretty up front, Josh Gorges and P.K. Subban on the blue line and Carey Price in net.
7:25 p.m.: The Bruins have officially scratched Josh Hennessy and Andrew Bodnarchuk, along with Nathan Horton, who will miss his ninth game with a concussion.
Aaron Palushaj and Travis Moen (upper body) are out for the Canadiens, who will dress seven defensemen. Scott Gomez and Andrei Kostitsyn are both playing, while Ryan White will make his season debut to add some needed toughness to the Habs.
7:15 p.m.: Based on warm-ups, it appears the Bruins won't be making any roster changes, with Andrew Bodnarchuk and Josh Hennessy expected to be scratched again. But there may be a lineup change though, with Milan Lucic skating with Chris Kelly and Jordan Caron and Benoit Pouliot with David Krejci and Rich Peverley.
That will bear watching to see if the new combinations remain for the start of the game.
7 p.m.: Tim Thomas will get the start again. He leads the Bruins out for warm-ups in Montreal, while Carey Price leads the Canadiens out.
That's the goalie matchup for this one.
It's the second straight time Thomas has played both ends of back-to-back games. He bounced back from a loss to Pittsburgh on Feb. 4 with one of his best recent efforts in Washington the following day, and the Bruins will be looking for similar results in this one.
6:30 p.m.: The Bruins and Canadiens will meet for the final time this season in about an hour.
It's a strange spring when the B's and Habs don't meet, and considering Montreal's position in 12th place in the East, the ancient rivals aren't likely to cross paths in the playoffs either.
It's been a strange season overall for the Habs, with the latest controversy coming Tuesday in practice when Scott Gomez clashed with assistant coach Randy Ladouceur. That could lead to Gomez, who recently ended a goal-scoring drought that lasted more than a calendar year, being a healthy scratch against the Bruins. Head coach Randy Cunneyworth termed both Gomez and Andrei Kostitsyn, who was benched late in Monday's loss to Carolina and dropped to the fourth line in practice on Tuesday, as game-time decisions for this contest.
12:30 p.m. ET: After dropping another game on Tuesday against the Rangers, the Bruins will look to get back on track when they open a season-high six-game road trip Wednesday night in Montreal.
It's the last meeting of the season between the bitter rivals, and it's unlikely they'll clash again in the playoffs this spring with Montreal (23-25-9, 55 points) sitting in 12th in the East, seven points out of the final playoff spot.
The Habs have actually played better than the Bruins of late though. Montreal fell 5-3 to Carolina on Monday, but prior to that rattled off four straight wins by a combined 15-4 score. That run included shutouts of Winnipeg and Toronto.
Shutouts are not something the Bruins (34-18-2, 70 points) want to hear about after losing 3-0 to the Rangers, Boston's third time being blanked in its last six games. Since their last meeting with Montreal, a 2-1 win at the Garden on Jan. 12, the Bruins are just 6-7-1.
The Bruins do have the edge in the season series with the Canadiens. Montreal swept a home-and-home back in October, winning 2-1 at the Bell Centre and 4-2 in Boston, but the Bruins have won the last three meetings, each by one goal. This one promises to be another close one, and one that the Bruins desperately need to win to start a crucial road trip on a good note and get moving in the right direction again.
The puck drops at 7:30 p.m., so check back here for updates on all the action.