Tyler Seguin and Patrice Bergeron scored for the Bruins, but David Krejci and Rich Peverley were stopped. Matt Hendricks and Alexander Semin also scored for Washington.
The Bruins don't clinch a playoff spot with the single point for the shootout loss, but the late rally to force overtime and earn that point does strengthen their hold on the top spot in the Northeast Division. Boston now leads Ottawa by six points, but no longer has a game in hand as both teams have five games remaining. The Bruins also remain four points up on Florida in the battle for the No. 2 seed in the East with the Panthers losing in overtime to Minnesota.
Boston hits the road for two games in New York, facing the Islanders on Saturday and the Rangers on Sunday.
End Overtime, 2-2: This one will be settled in a shootout. The Caps had a late chance but Ovechkin missed from the right slot with 23 seconds left, and now it will come down to the breakaway competition.
Overtime, 4:44, 2-2: The Bruins with the best chance in a fast-moving overtime as Brad Marchand fires a shot from the right slot and Johnny Boychuk follows up trying to stuff it home at the right post in a wild scramble in the crease.
The Capitals use their timeout after the whistle with a key faceoff coming in the Washington zone.
Overtime, 0:00, 2-2: The five-minute sudden death extra session is under way. the teams will skate 4 on 4 to try to earn the extra point in this one.
End Regulation 2-2: This one will be going to overtime. The Bruins strike twice in the closing minutes to earn at least a point, but still need the second point to clinch a playoff spot.
Third Period, 18:44, 2-2: The Bruins pull even with another late strike, this one from Andrew Ference.
The Boston defenseman fired in a shot from just inside the center of the blue line through a screen in front to tie it. Thomas was still in the net, as the Bruins had yet to pull him for the extra attacker.
Third Period, 16:50, Capitals 2-1: The Bruins are back in this one late as they cut the deficit to one.
Zdeno Chara sent in the shot from the blue line with David Krejci and Rich Peverley providing the screen in front. Krejci got a piece of it going by and gets the goal.
Third Period, 16:05, Capitals 2-0: The hitting continues as Ovechkin catches Gregory Campbell and levels him in the Capitals zone.
Third Period, 14:23, Capitals 2-0: Things are heating up a bit. Zdeno Chara manhandled Matt Hendricks throughout that shift, sending him down several times. But Hendricks got the last shot, coming in low and taking down the big blueliner behind the net.
Third Period, 13:24, Capitals 2-0: The Bruins have again shuffled their lines up front, putting Tyler Seguin back with Brad Marchand and Patrice Bergeron, while Rich Peverley moves up with David Krejci and Milan Lucic.
Third Period, 9:54, Capitals 2-0: The Capitals strike again, this time with Marcus Johansson scoring off an Ovechkin feed,
That pair broke in 2 on 1 with Chara back. Ovechkin carried the puck down the left wing and crossed it over to Johansson. he broke his stick on the shot, but got enough on it to get it past Thomas.
Third Period, 7:59, Capitals 1-0: The Capitals finally break the ice, and its ex-Bruin Dennis Wideman with the goal.
Wideman took a drop pass from Alex Ovechkin and fired a shot that beat Thomas uo high from the slot.
Third Period, 4:52, 0-0: The Krejci line with a strong shift creating pressure in the Washington zone, but even with Caps defenseman Dennis Wideman caught without a stick the Bruins couldn't put one of those opportunities home.
Third Period, 2:27, 0-0: Patrice Bergeron has a chance driving hard to the net, but loses control of the puck trying to go to the backhand in front and can't get a shot off.
Third Period, 0:00, 0-0: The final frame is under way here at the Garden, but it won't be the final frame unless somebody finally scores. The Bruins can clinch a playoff spot with a win, while the Caps are trying to claw back into a playoff position.
Second Intermission Notes: The Bruins and Caps are still struggling to get anything going offensively. Boston has a 15-9 edge in shots, but that was just 8-7 in the second and neither team has been particularly accurate with their shots so far.
Boston has put just 15 of 43 attempts on net, with 13 others blocked and 15 missing the net. The Caps have nine shots on goal on 24 attempts (7 blocked, 8 missed).
The Bruins did ramp up their physical game in the second. After being outhit 8-4 in the first, they had a 14-2 edge in the second for an 18-10 overall lead. Johnny Boychuk leads the way with four, followed by Greg Zanon with three. The Bruins are also controlling the draws, going 22-14 on faceoffs (61 percent). As usual, Patrice Bergeron is leading that effort at 14-5.
End Second Period, 0-0: the middle frame comes to a close with the game still scoreless. Neither goalie has been especially busy, with the Bruins managing 15 shots on goal and the Capitals just nine.
Second Period, 18:11, 0-0: The Caps have come alive with three whole shots in the last minute. That ups their total in the game to nine as they remain short of double digits with the second period nearly complete.
Second Period, 15:08, 0-0: Milan Lucic finishes a big hit on Cody Eakin the Washington zone. That's some payback for the hit Eakin put on Lucic in the first period.
Second Period, 13:08, 0-0: The Bruins kill that penalty off without allowing a shot as the sides return to even strength. Boston's penalty killers get a nice ovation from the Garden faithful as the penalty expires.
Second Period, 11:08, 0-0: The Bruins will have to kill off their first penalty of the night as David Krejci is called for high-sticking. Boston is up 14-6 in shots, but it remains a scoreless draw more than halfway through this game.
Second Period, 8:44, 0-0: The Bruins come right back with their best chance of the night. Greg Zanon sent a shot in from the point that hit the post, then the back of Neuvirth's leg. Bergeron tried to bang home the rebound from the left side below the goal line but it stayed out.
Second Period, 8:21, 0-0: Washington with a rare chance as Alex Ovechkin uses his speed to get outside down the right wing and feeds Brooks Laich in front for a shot from the slot that Thomas turned aside.
Second Period, 4:50, 0-0: The Capitals get their first shot of the period and just their third shot of the game nearly five minutes into the second with a Mike Green point shot. The Bruins have just nine shots in the game.
Second Period, 2:00, 0-0: The Bruins have announced that Adam McQuaid will not return to the game after being injured in the first period on hit from Jason Chimera.
Second Period, 0:00, 0-0: The middle frame is under way here at the Garden. Adam McQuaid has not returned to the Bruins bench to start the second.
First Intermission Notes: The Bruins and Capitals have both struggled to get anything going offensively so far, though the Bruins are at least trying.
Boston has attempted 25 shots to just six for Washington, but only seven of those attempts have reached the net. Nine others were blocked and nine missed the net. Wasington got two of their attempts on Tim Thomas, with three others blocked and one missing.
The Bruins were helped in compiling that shot advantage by the five-minute power play late in the first, but the inability to cash in on that chance could prove costly in this game. The severity of the injury to Adam McQuaid on the play could be far more costly going forward.
Washington also has an injury issue to deal with, as starting goalie Tomas Vokoun left late in the first. He was playing his first game since March 16 after suffering a groin injury and may have re-injured that. Michal Neuvirth came on in relief with 1:35 left, but did not face a shot before the end of the period.
End First Period, 0-0: The opening frame has come to a close with neither team scoring despite the Bruins holding a 7-2 advantage in shots. The bigger concern is the condition of Adam McQuaid, who went off injured late in the period after a hit that earned Jason Chimera a five-minute major and game misconduct.
First Period,19:00, 0-0: The Bruins created some chances, but could not convert on the five-minute power play and the sides are now back at even strength.
First Period,18:25, 0-0: The Capitals have switched goalies as Tomas Vokoun headed to the locker room. He was in his first game back from a groin injury and may have aggravated it. Michal Neuvirth is now in goal for Washington.
First Period,14:00, 0-0: The Bruins will be going on a five-minute power play, but it comes at the cost of an injury to Adam McQuaid. McQuaid was hurt on a hit from behind by Jason Chimera, who gets a major for charging and a game misconduct.
McQuaid was turning as Chimera hit him and went face first into the boards behind the Bruins net. He was down for several minutes and helped to the locker room holding a towel to his face with an apparent cut.
First Period,11:19, 0-0: Rich Peverley fires wide on a bid from the right slot and there have still been just three shots combined more than halfway through the opening period. The Bruins have two to the Caps' one.
First Period, 7:18, 0-0: The Bruins had their best scoring chance yet when Zdeno Chara fired in a shot from the left point and the rebound went right to Brad Marchand alone along the goal line to the right of the cage, but Marchand couldn't get the bad-angle shot on net.
First Period, 5:10, 0-0: The physical play is picking up a little in the early going, but it's a guy who usually dishes out the hits that was on the receiving end. Milan Lucic was nailed hard into the boards in front of the Bruins bench by Cody Eakin.
First Period, 3:19, 0-0: Bit of a slow start to this one with neither team putting a shot on goal yet and the Bruins' timing a bit off with back-to-back offsides trying to gain the Washington zone.
First Period, 0:00, 0-0: This one is under way here at the Garden, where the Bruins can clinch a playoff spot with a win over Washington.
7 p.m.: The Bruins will open this one with the red-hot third line of Benoit Pouliot, Chris Kelly and Brian Rolston up front, with Greg Zanon and Joe Corvo on defense and Tim Thomas in goal.
The Capitals counter with ex-Bruin Mike Knuble, Jay Beagle and Matt Hendricks up front, with Roman Hamrlik and Mike Green on the blue line and Tomas Vokoun in net.
6:50 p.m.: The Bruins have officially scratched Daniel Paille once again, along with Mike Mottau and Torey Krug. Dennis Seidenberg (leg laceration) and Tuukka Rask (groin) are out with injuries.
John Erskine, Jeff Halpern, Joel Ward and Jeff Schultz are out for Washington.
6:45 p.m.: Based on warm-ups, the Bruins will be going with the same forward lines, while Joe Corvo replaces the injured Dennis Seidenberg on defense.
The full line combinations from warm-ups:
6:40 p.m.: Torey Krug, a free-agent defenseman out of Michigan State signed earlier this week, is taking his first warm-up with the Bruins.
He was not in the line rushes and won't be playing, but Claude Julien has used warm-ups in the paast to help youngsters get acclimated to the NHL as they adjust to the pro game.
6:30 p.m.: It's a Thomas vs. Tomas showdown at the Garden.
Tim Thomas and Tomas Vokoun lead their respective clubs onto the ice for warm-ups. That will be the goaltending matchup in this one.
6 p.m.: The Bruins will get a chance to clinch a playoff spot when they take on the Capitals here at the Garden in about an hour.
Washington's playoff hopes are a little dimmer, but the Caps are still alive, sitting in ninth place just two points out of the final spot in the East.
They should be a desperate bunch in this one, and the Bruins will have to face them without defenseman Dennis Seidenberg. He will miss his first game of the season with an infection in his leg from a cut from a skate originally suffered Saturday in Los Angeles. Joe Corvo will return to the lineup to replace him.
The Bruins will still have an intimidating presence on the blue line, as Adam McQuaid has once again unveiled his frightening buzz cut/mullet hybrid after Wednesday's Cuts for a Cause event.
Tim Thomas was the first goalie off the ice at the morning skate and is expected to get the start, with Tomas Vokoun returning from a groin injury to start in net for Washington.
8 a.m. ET: The Bruins have strung together three straight victories, their longest win streak since a seven-game run all the way back in December.
But extending that streak to four won't be easy when a desperate Washington Capitals club comes to the Garden on Thursday.
Washington is battling for its playoff life, currently sitting in ninth place in the East. The Capitals are two points behind Buffalo for the final playoff spot after dropping a 5-1 decision to the Sabres on Tuesday. But Washington was 6-2-2 in its previous 10 games, making a late push for the postseason after a disappointing campaign.
The Bruins still have plenty to play for themselves as they look to lock up the Northeast Division crown and the second seed in the East. Boston is up by five points on Ottawa with a game in hand in the battle for the division crown, and the Bruins lead third-seeded Florida by four points.
Obviously, the Capitals will have even more urgency in this one, but Bruins coach Claude Julien said he welcomes the challenge of facing a desperate foe to help prepare his club for the intensity of the upcoming postseason.
"I think for us it's great," Julien said after Wednesday's practice. "It's the kind of competition we need this time of year to get ourselves ready for the playoffs. If you can't handle those kind of games now, how are you going to handle them in a couple weeks? I don't mind those at all. I think it's going to be a great title [Thursday], and I'm looking forward to it."
The Bruins have already lost twice to the Capitals this season, falling 5-3 in Washington on Jan. 24 and 4-3 at the Garden on March 10. Boston did win the meeting in between, prevailing 4-1 in Washington on Feb. 5.
The Capitals could get goalie Tomas Vokoun back for this game. He's been out since March 16 with a groin injury. Center Nicklas Backstrom, sidelined since Jan. 3 with a concussion, is traveling with the team but has been ruled out for Thursday.
The puck drops at 7 p.m. Tune in to NESN to watch the game, and stay with the NESN.com live blog, as we'll keep you up to speed on everything happening at the Garden.