For those in Black & Gold, however, that dream ended with 1:36 remaining when Toronto forward James van Riemsdyk fired home a shot from the top of the right circle put the Maple Leafs ahead for good.

The marker erased two noble comebacks from the Bruins and clinched a 6-5 victory for the Leafs at TD Garden.

Video: BOS Recap: Bruins' rally falls short in 6-5 loss

Boston fought back from a three-goal deficit to tie the game midway through the third period, before knotting things again with less than three minutes remaining. It was a valiant effort that fell just short.

"Tough one," said Bruins captain Zdeno Chara. "We got ourselves in trouble in the second, but we found a way to come back and score some big goals, create such a positive momentum and lots of energy. It was fun to be playing that way.

"Going into the third, we knew we had to keep the foot on the gas and keep pressure on them and we got rewarded. But again, missing guys on the backcheck, or having sticks in the right position, closing on defensive zone coverage, things like that.

"It just seemed like every time we missed one of those, the puck ends up in our net. Those are details."

What makes the loss even tougher for the Bruins is it came against a divisional opponent that is breathing down their necks. A win for Boston could have opened up a five-point lead over the Maple Leafs. Now, Toronto sits just one point behind the Bruins in the Atlantic Division, with five games in hand.

Video: Chara discusses 6-5 loss to Leafs

"We knew how important those two points in that game was and it's very disappointing and frustrating at the same time," said Patrice Bergeron. "You can't give up six goals if you want to win any hockey game."

The defensive miscues have become an increasing area of concern for the Bruins, who have now surrendered 23 goals over their last six games.

"I wish I had an answer for you," Adam McQuaid said of the problems defensively. "We made mistakes and they capitalized on them. We knew coming in that they were capable of doing that.

"I don't have an answer as to why, but it's not like we weren't aware that they were going to try to capitalize on mistakes and turnovers and they have the skillset to do so."

Video: Julien discusses 6-5 loss to Leafs

It was McQuaid who jumpstarted the Bruins comeback. After William Nylander's third goal of the night gave Toronto a 4-1 lead and chased Tuukka Rask from the game at 10:17 of the second, David Pastrnak cut into the deficit only 38 seconds later with his second of the game to make it 4-2.

McQuaid then took things into his own hands - literally - and sent Boston on its way.

The rugged defenseman dropped the gloves with Matt Martin just under two minutes after Pastrnak's tally and, in what was an incredibly spirited bout, dropped Martin with a heavy right to the chin.

"Not really thinking, things happen really quick - not really much time to think about stuff like that," said McQuaid. "I think I finished my hit on [Auston] Matthews there down in the corner. I was skating back up the ice and he jumped on."

Video: TOR@BOS: Spooner buries blocked shot on the doorstep

Torey Krug added a power-play goal at 15:53 of the second, before Ryan Spooner completed the comeback by potting a rebound from out front midway through the third period to knot the game at 4.

"A lot," Bergeron said of how much the team fed off McQuaid's bout. "I mean, that was obviously an amazing fight by both guys. They were really going at it. They're both very honest players for their team.

"And Adam, like I've said before, he's always been a huge influence on a lot of guys and he's very quiet but he always works hard and goes about his business and stands up for his teammates, and, again right there, that gave - definitely lots of energy."

Toronto, though, was not interested in going quietly into the night, as Connor Brown notched a go-ahead goal with 4:45 remaining. But, once again, the Bruins stormed back.

Bergeron answered 1:51 later with Boston's second power-play goal of the game to make it 5-5 and send the Garden into a frenzy.

Video: TOR@BOS: Bergeron nets game-tying PPG on backhand

"After they scored that fourth goal," Bergeron said, "I thought we took over, took control…"

The Maple Leafs had other ideas. Van Riemsdyk's tally with 1:36 left finally closed the door on a Toronto victory.

"If you lose that focus and you don't always remind yourself what is your job on every possession and every time you are on the ice, then things are probably not going to happen the way that you want them to happen," said Chara, who had three assists for the first time since March 2012, tying a career high for points in a game.

"So, you always have to be consistent and sharp and thinking ahead a little bit about your job."

Plenty of energy. Five goals scored. A well-timed fight. And two vigorous comebacks. The Bruins hoped it all would be enough.

But the positives did not quite outweigh the mistkaes. And, in the end, it goes into the books as a loss.

"When they're down 4-1, they didn't pack their bags and leave," Claude Julien said of his team. "We fought back. So, you like those kinds of things. But at the end of the night, it's about winning hockey games.

"And I have to say that, tonight, we found a way to lose. So that's the disappointing part."

Video: Bergeron discusses 6-5 loss to Leafs