ST. LOUIS -- Rookie goalie Jordan Binnington blamed himself after getting pulled for the first time in his NHL career as his St. Louis Blues were routed by the Boston Bruins 7-2 in Game 3 of the Stanley Cup Final on Saturday night.

"I gotta be better. I gotta do a better job giving my team a chance to win. They scored three goals in the first. That's never good," said Binnington, who gave up five goals on 19 shots before being replaced by Jake Allen at 6:29 of the second period, with the Blues down 5-1. "It is what it is, right? It's a loss. I'm not happy with that."

Binnington's teammates and coach were quick to defend him, saying it was a disastrous performance in front of the goalie that necessitated his departure.

"I don't think we played well enough in front of him," center Ryan O'Reilly said. "He made some huge saves early that gave us a chance. We just didn't play our usual selves the way we defended, and that's hard on any goalie. There's not much you can do when you give them that many PPs (power plays) and that many opportunities. It's not him; it's the guys in front of him. We have to do a better job."

The Bruins took a 3-0 lead in the first period on a power-play goal from Patrice Bergeron at 10:47, a wrist shot from Charlie Coyle at 17:40 and a goal from Sean Kuraly with 9.1 seconds left.

Binnington was chased at the 12:12 mark of the second period after Torey Krug scored the Bruins' third power-play goal of the game. He was replaced by Allen, the Blues' former starter, who last appeared in a game April 3.

Game 3 continued two systemic problems for the Blues, who trail in the series 2-1. Most concerning is their inability to stay out of the penalty box; the Bruins have had 14 power plays in the first three games.

"It's the major issue," O'Reilly said. "Keeping the 5-on-5 game and being more disciplined. It's tough to say [what's happened]. Maybe fatigue's kicking in. That can be an issue. But we all know we have to be better and not get sucked into stuff, and support each other better."

The Bruins were only 2-for-10 on power plays entering Game 3, but they found their groove Saturday, going 4-for-4 and needing just 2:06 for those tallies. Statistically, the Bruins' power play is the best in the playoffs since the New York Islanders in 1981. Boston showed it in Game 3.

"We know they have a dangerous power play, and we've been flirting with danger here the whole series and it burnt us tonight," Blues coach Craig Berube said.

The coaching staff helped light the fire. The Blues challenged Kuraly's goal with 9.1 seconds left in the first period, believing there was an offside. But since Blues defenseman Joel Edmundson played the puck into his own zone, the goal stood and St. Louis was given a delay-of-game penalty. On the ensuing power play, David Pastrnak scored just 41 seconds into the second period for the 4-0 lead.

Berube believed there was a "50-50" chance officials would overturn the call. O'Reilly defended the missed challenge.

"Obviously, them having a 3-0 lead, we want to wipe that period away and then you come out and you're killing. It's tough," he said. "I think they've got to make that challenge. It was close. It's unfortunate it puts them on the PP and then they get one again right off the bat. It took the wind right out and any chance of that early push that we needed at the start of the second."

Then there's Binnington.

He has given up five goals in the first period over the past two games. Binnington's .737 save percentage in Game 3 was his worst in any appearance in his NHL career, regular season or postseason. He's typically a model of cool during games, to the point where he sometimes doesn't even celebrate victories. But in Game 3, he bumped Boston goalie Tuukka Rask as the two skated to the benches during a TV timeout in the second period, and later admitted frustration.

"It was a 4-0 game. I wasn't happy. It's how I reacted. It's a long series, right?" he said. "It's something I did, and we're moving on."

Moving on is something Binnington and the Blues have done effectively during the playoffs, to the point where it's become the Calder Trophy finalist's calling card. Binnington is 6-2 with a 1.84 goals-against average and a .935 save percentage following a loss in these playoffs. Only five goalies in NHL history have posted more wins after defeats within a single postseason.

"My confidence level's really high [in Binnington]," Berube said. "Five goals he allowed, so he had seen enough. So we just wanted to pull him and get him ready for the next game."

Binnington said he'll be ready come Monday for Game 4.

"Your approach is the same," he said. "It's the Stanley Cup Final. Lots to play for. You prepare the same way. Believe in your teammates. And believe in yourself. Gotta do your job."