ST. LOUIS — The puck took one hop and then another, bouncing right past Blues goaltender Jordan Binnington, who turned to watch it skip over the goal line before dropping his head back in resignation. St. Louis had waited 51 seasons for the Stanley Cup to be in the building, and a 58-foot dribbling shot by Boston’s Brandon Carlo all but ensured the trophy would stay locked in its case for a few more days.

For the first time since 2011, the Stanley Cup finals are going seven games after the Bruins’ 5-1 win Sunday night at Enterprise Center. This one came down to Boston’s superior special teams and the goaltending, both Tuukka Rask’s brilliance and Binnington’s gaffe on Carlo’s long-range shot in the third period. It had been a one-goal game to that point and, after Carlo scored at 2:31, Karson Kuhlman, playing in just his seventh game of these playoffs, extended Boston’s lead at 10:15.

Blues center Ryan O’Reilly finally gave St. Louis fans something to cheer about less than two minutes later with a shot that just barely beat Rask’s extended pad — a video review confirmed the puck just barely got completely across the goal line — but the Blues couldn’t get on the board again as Rask finished with 28 saves. David Pastrnak added a fourth tally for the Bruins with 5:54 left, and captain Zdeno Chara had a late empty-netter.

“You’ve got two good teams that have gone toe to toe here,” Boston coach Bruce Cassidy said. “The whole hockey world loves a Game 7. May the best team win.”

As blue-clad fans blanketed downtown for a watch party outside the arena and local newspaper ads congratulating St. Louis on its first championship prematurely leaked online, Boston’s Jake DeBrusk said it all became fodder for motivation. But the biggest inspiration came from alternate captain Patrice Bergeron, who addressed the team.

“It made us all want to run through a wall,” DeBrusk said.

“It was exactly what we needed,” defenseman Charlie McAvoy said. “It was an element of what the dream is. Growing up, every one of us shares the same dream. ... We were all a little kid once, and we all wanted this bad. And I think it was just an element of savoring this moment and not letting it end tonight. It was exactly what we needed, and he stepped up. When he talks, you listen.”

“Nerves are good,” Blues coach Craig Berube said Saturday. “It means you care. I don’t think our group, if you talked to most of the guys, have strayed away from their mindset. We’ve just been preparing the same way. (Stanley Cup) in the building or not, we know what’s at stake.”

What started as a raucous crowd got quiet after Boston scored the first goal. St. Louis forward Brayden Schenn was penalized for boarding Joakim Nordstrom 7:17 into the game, and as O’Reilly attempted a clear on the penalty kill, he backhanded the puck over the glass for a delay-of-game penalty. That gave the Bruins a two-man advantage, and Brad Marchand needed just 21 seconds to score from the right faceoff circle.

Meanwhile, St. Louis’ power play entered in a 1-for-14 slump for the series, a streak that extended to 1 for 18 on Sunday night. The Blues didn’t capitalize on their first two power plays, and they had a third man advantage 9:11 into the second period after Marchand was whistled for tripping Alex Pietrangelo.

That’s when St. Louis had its best chances, such as defenseman Colton Parayko tipping the puck just wide at point-blank range. Then Pietrangelo’s backhand clanged off the post and the bouncing puck nearly got past Rask, who made a behind-the-back save. He has been the Bruins’ best player this postseason, entering Game 6 with a .937 save percentage and a 1.97 goals against average through 22 games. Rask finished with 12 saves when the Blues were on the power play.

“He’s our best player, and he has been all playoffs,” McAvoy said.

Rask finished with 12 saves when the Blues were on the power play.

The Bruins felt they had been “screwed,” as Cassidy put it, by the officiating in their 2-1 loss Thursday in Game 5. The Blues’ Tyler Bozak tripped forward Noel Acciari — and was not penalized — moments before David Perron scored what became the game-winning goal, and Cassidy’s remarks after the game were pointed, referring to the refereeing this postseason as a “black eye” for the NHL. He also implied that the Blues were getting more calls and noncalls in their favor because Berube had complained about penalties earlier in the series.

“Our play should define us, not a call,” Cassidy said Friday. “It will be part of the message.”

The Bruins responded with four penalty kills through 40 minutes Sunday, a gutsy performance for a roster that’s hurting.

Chara played a second straight game with a full cage on after a shot hit him in the face during Game 4, reportedly breaking his jaw. Chara wouldn’t say whether he has been able to eat properly, and just speaking at all has been challenging for him. Boston’s top-line stars Patrice Bergeron and Marchand are also believed to be playing through injuries, and the line still hasn’t scored at five-on-five in this series.

Rask has been the team’s ultimate eraser, and while he was on the Boston team that won the championship in 2011, he didn’t play in that postseason. But those Bruins were the last team to win a Game 7 in the Stanley Cup Final — when they beat Vancouver in 2011 — and they’ll get a chance to do it again Wednesday night.

“The emotions, like, crap, it’s a lot,” McAvoy said. “Our backs are against the wall, and you have so many mixed emotions. You do whatever it takes. ... But I got a different perspective when our guys stepped up and just talked. It was an element of honesty to it, about being in this position and knowing that if we just do our jobs, we’re a family. ... “Just the thought of it being over tonight was terrifying. We’d come all this way. We come together when it matters, and I think tonight was just a good example of that.”