Roy beat Tuukka Rask as he came down wide right, cut to the net and roofed a backhander off the post and in. Benoit Pouliot missed the net in his attempt to extend the shootout, and the Sabres take the win in Buffalo.
David Krejci scored on Boston's first attempt, while Tyler Seguin and Patrice Bergeron were stopped. Rask denied Jason Pominville and Nathan Gerbe, but Thomas Vanek scored on a slap shot in the second round.
The Bruins still haven't won back-to-back games since Jan. 10 and 12, but they do earn points in consecutive games for the first time in over a month, last accomplishing that with a 2-0-1 stretch from Jan. 19-22.
The Bruins will get right back to work on Saturday, closing out their six-game road trip in Ottawa against their closest pursuer in the Northeast Division.
End Overtime, 1-1: This one will be settled in a shootout. Both teams had chances in overtime, but Rask and Miller each made big saves to push them one to a skills competition.
Overtime, 3:38, 1-1: The Sabres mount their first pressure in a while, but Rask makes several stops, including a diving save to rob Vanek at the right post.
Overtime, 1:36, 1-1: The Bruins aren't able to convert that power-play chance and Vanek is out of the box as the sides return to even strength.
Overtime, 0:00, 1-1: The five-minute extra session is under way, with the Bruins now on a 4-on-3 power play to start the sudden-death period.
End Regulation, 1-1: This one won't be settled in 60 minutes. Both teams earn a point, and now will battle for the second one with the Bruins opening the extra session on the power play.
Third Period, 19:36, 1-1: The Bruins will end regulation and could go into overtime on the man advantage as Thomas Vanek goes off for two minutes for high-sticking Johnny Boychuk.
Third Period, 19:03, 1-1: Tempers flare a bit after the Bruins are whistled for offsides. Paul Gaustad tries to go after Marchand, but the Bruins agitator won't take the bait and avoids any costly late penalties.
Third Period, 17:40, 1-1: The Bruins get another strong shift from the Campbell line as Boston keeps the ice tilted in their direction this period, but they still get get the go-ahead goal past Miller.
Third Period, 15:44, 1-1: The Bruins continue to press the attack in the third period. Boston now with a 13-5 edge in shots in this frame after coming into the period tied 18-18 in that category.
Third Period, 11:49, 1-1: The Bruins fire another shot on Miller and we get the first bit of bad blood so far with some shoving after the whistle. No penalties come from the mild scrum in what has been a very peaceful game so far between these rivals.
Third Period, 9:05, 1-1: The Sabres threaten with a shot by Derek Roy and a rebound attempt by Jason Pominville along the goal line, but Rask comes up with the stops to keep this one tied.
Third Period, 6:40, 1-1: Things have really opened up here in the third period. After a tight defensive game in the first two periods, both teams have traded chances since the Bruins tied it early in the third.
Third Period, 3:36, 1-1: The Bruins pull even as Zdeno Chara ties it with a power-play blast.
Chara intercepted a Derek Roy clearing attempt and launched a shot from the right point past Miller.
Third Period, 2:45, Sabres 1-0: The Bruins fourth line creates a series of chances with shots by both Campbell and Paille. That pressure eventually forces Christian Ehrhoff to fire the puck out of play and take a delay of game penalty, giving the Bruins another power-play chance.
Third Period, 0:00, Sabres 1-0: The final frame is under way in Buffalo, where the Bruins will look to rally from a one-goal deficit to post their first back-to-back wins since early January.
Second Intermission Notes: The Bruins will need a big third period to finally get their second straight win after Buffalo struck for the game's only goal so far in the second period.
Other than the score, the game has been about as even as possible. the shots are tied 18-18, faceoff wins even at 15-15, the Bruins have a slim 11-9 edge in hits and the Sabres are up 10-9 in blocked shots.
The Bruins have had the only two power-play chances of the game so far, but failed to generate many chances with the man advantage. Boston had just one shot in the four minutes of power-play time.
David Krejci continues to perform well in the faceoff dot, going 7-1 on draws. That's helped overcome linemate Chris Kelly's 1-5 mark so far. Kelly does lead the bruins with four shots though, to go with two blocked shots and a hit, while Krejci has three shots.
End Second Period, Sabres 1-0: The middle frame ends, but not before Buffalo finally breaks the ice and takes a one-goal lead into the third period.
Second Period, 18:20, Sabres 1-0: Chris Kelly pounces on a loose puck in the slot for a scoring bid after a Buffalo clear hits a skate and bounces to the Bruins forechecker, but Miller comes up with another stop.
Second Period, 17:46, Sabres 1-0: The Bruins can't convert that power-play chance either as the sides are back to even strength.
Second Period, 15:46, Sabres 1-0: The Bruins will get another chance on the power play as Corey Tropp goes off for tripping once again, this time upending Benoit Pouliot.
Second Period, 14:45, Sabres 1-0: The Sabres strike first as Andrej Sekera takes advantage of a Bruins defensive breakdown.
The Sabres defenseman pinched in from the right point and Brad Marchand doesn't pick up his check as Sekera collects the pass and fires home the shot from the right circle.
Second Period, 13:54, 0-0: The Bruins don't do anything with that power-play chance, failing to get a shot on goal as they struggled to even get set up in the offensive zone.
Second Period, 11:54, 0-0: The Bruins will get the first power-play chance of the night as Corey Tropp is called for tripping after catching Rask with a skate trying to get to the front of the net.
Second Period, 11:33, 0-0: The Sabres continued to create chances, but the Bruins are doing a good job of getting into the shooting lanes and blocking attempts before they can even reach Rask.
Second Period, 8:36, 0-0: The Sabres with some sustained pressure on the Bruins, who are struggling to clear the puck but keeping Buffalo largely to the perimeter to prevent any real strong scoring chances.
Second Period, 6:42, 0-0: The Bruins now with some chances, as David Krejci is denied twice by Miller. The first came as he curled around a defender for a shot from the right slot. The second came on a redirection of a Patrice Bergeron shot in front.
Second Period, 5:50, 0-0: The Sabres threaten as as Derek Roy gets around Chara, setting up a chance for Jason Pominville, but Rask smothers the shot to keep it scoreless.
Second Period, 0:58, 0-0: Tyler Seguin with a steal and chance in front, but Miller makes the save as it's the Bruins that nearly score in the opening minute of this period.
Second Period, 0:00, 0-0: The middle frame is under way in Buffalo, with the Bruins and Sabres still searching for the first score of this one.
First Intermission Notes: There was plenty of up-and-down action, but not really a lot of the energy or nastiness expected of games between these rivals this year as the Bruins and Sabres remain scoreless after one period.
Buffalo has a slim 8-7 edge in shots, but Tuukka Rask has been solid so far after allowing three goals on 10 shots before being pulled in his last visit to Buffalo.
Boston has an 8-4 edge in hits, but there really hasn't been a lot of physical play so far. Drew Stafford did go off after a collision with David Krejci, but returned later in the period. Krejci, meanwhile, has looked good again on the wing, created a couple of scoring chances. He is still playing right wing, but is taking the bulk of the draws on that line, and is 5-0 so far on faceoffs. the rest of the Bruins are just 3-6 on draws.
End First Period, 0-0: The opening frame ends in a scoreless deadlock, though both teams had threats in the final minute, the Sabres' coming on a Tyler Ennis bid at the right post in the final seconds.
First Period, 16:25, 0-0: The Sabres nearly open the scoring as Thomas Vanek gets the puck away from Adam McQuaid at the point and breaks down the left wing for a bid, but can't put it past Rask.
First Period, 14:48, 0-0: The Bruins create another chance as Krejci breaks down the left wing, stops and fires in a shot. The Bruins jam at the rebound but Miller is able to tie it up for the faceoff.
First Period, 11:22, 0-0: Drew Stafford goes down awkwardly after a collision at center ice with David Krejci. Stafford stayed down briefly, then limped to bench and eventually headed down the hallway to the locker room.
First Period, 8:16, 0-0: The Bruins get their best chance thus far, but Zdeno Chara's blast from the point clangs off the crossbar as Miller appeared to just get a piece of it.
First Period, 7:25, 0-0: Rask gets away with a dangerous clear, as Nathan Gerbe just misses picking off the puck with a wide open net in front of him.
First Period, 5:21, 0-0: Not quite the same frenetic pace as the start in St. Louis as there hasn't been much in the way of scoring chances early outside of that one flurry in the opening minute by the Sabres.
First Period, 0:44, 0-0: The Sabres come within inches of scoring in the opening minute as Johnny Boychuk is caught out after breaking his stick and Buffalo nearly scores on a wild scramble in the crease.
First Period, 0:00, 0-0: And this one is under way up in Brad Marchand's favorite city, where the Bruins hope to fare better than they did in their last visit to Buffalo.
7:30 p.m.: The Bruins will open with David Krejci and Milan Lucic flanking Chris kelly up front, with Dennis Seidenberg and Joe Corvo on defense and Tuukka Rask in goal.
The Sabres counter with Thomas Vanek, Derek Roy and Jason Pominville up front, Jordan Leopold and Tyler Myers on the blue line and Ryan Miller in net.
7:25 p.m.: Despite the extra turns in the line rushes in warm-ups, Josh Hennessy will remain a scratch for another games. Jordan Caron stays in the lineup, Hennessy and Andrew Bodnarchuk are the healthy scratches.
The Sabres are without Brad Boyes and Cody McCormick with injuries and Marc-Andre Gragnani is a scratch.
7:15 p.m.: It appears the Bruins may play both Carter Camper and Josh Hennessy. They skated together with Benoit Pouliot in the warm-ups.
If that holds, Jordan Caron would be the odd man out, with the other lines remaining unchanged. David Krejci remains on the right wing again with Chris Kelly and Milan Lucic, Patrice Bergeron is still between Brad Marchand and Tyler Seguin and Gregory Campbell with Daniel Paille and Shawn Thornton.
7 p.m.: Tuukka Rask did lead the Bruins out for warm-ups in Buffalo and will be getting the start in this one.
Ryan Miller is in goal for the Sabres as expected.
6:30 p.m.: The Bruins return to the East, but not home just yet, as they will take on the division-rival Sabres in Buffalo in about an hour.
Boston's last visit to Buffalo ended in a 6-0 defeat, with Tuukka Rask pulled after allowing three goals on 10 shots. But it appears Rask may get a shot at redemption. He was the first goalie off the ice at the morning skate, traditionally an indication of who will be starting that night.
The warm-ups will reveal if Rask is indeed in the net for this one, but it would put Tim Thomas in line to start Saturday in Ottawa, where he has been dominant throughout his career.
8 a.m. ET: The Bruins finally snapped out of their recent funk with an impressive 4-2 win in St. Louis on Wednesday. Now they'll try to win back-to-back games for the first time since Jan. 10 and 12 when they return to Buffalo on Friday.
To do that, the Bruins (36-20-2, 74 points) will need to play much better than they did in their last visit to Buffalo. Boston suffered a season-worst 6-0 loss against the Sabres on Feb. 8, as Buffalo exacted a little revenge for its division rivals' earlier clashes this season.
The Bruins won both prior meetings back in November, rolling to a 6-2 win in Boston and rallying for a 4-3 shootout win in Buffalo. But the final scores weren't the big story, as that first meeting is best remembered for Milan Lucic steamrolling Ryan Miller when the Sabres netminder strayed too far out of the crease. The Sabres did nothing to stand up for their goalie in that game, and Lucic handled Paul Gaustad easily in an early bout in the first rematch in Buffalo.
The bad blood continued on Feb. 8 with three more fights, four misconducts and 80 penalty minutes. The Bruins were charged with 47 of those PIMs and did not have a power play in the game.
The Sabres have played better of late with a 7-3-2 mark over their last dozen games, but still are six points out of the final playoff spot in the East and under .500 at 26-27-7 (59 points).
The puck drops at 7:30 p.m., so check back here for updates on all the action.