BOSTON -- Bruins president Cam Neely hurled a water bottle against a wall. Boston fans littered the ice with garbage. Coach Bruce Cassidy called it "egregious," in an intense rant about how the quality of playoff officiating has been a "black eye" for the NHL.

The St. Louis Blues won Game 5 of the Stanley Cup Final 2-1 to take a 3-2 series lead Thursday night, but it was how they scored their second goal that had the Bruins' faithful irate. Moments before David Perron snuck a puck past Tuukka Rask, the officials opted not to call what appeared to be a blatant trip on Bruins forward Noel Acciari by Blues center Tyler Bozak. Acciari hit his head on the ice, taking him out of the play, and eventually putting him into the NHL's concussion protocol.

"The reaction was 'You missed an F'ing call,' that was what was being said on the bench, for obvious reasons," Cassidy said. "The no-call on Acciari ... their player is on his way to the box. It's right in front of the official. It's a slew foot. Our guy's gone. The spotter took him out of the game for a possible concussion. I mean, it's blatant. It had a big effect on the game."

Bozak said the play was "just a puck battle" and wasn't sure what had happened. "I honestly don't know. It's a fast game out there. I couldn't tell," Bozak said. "I was just battling for the puck. Luckily we ended up with it, and it ended up in the back of the net, so we'll take it."

NHL senior vice president and director of officiating Stephen Walkom was asked by a pool reporter to respond to the non-call. "We don't make comments on judgment calls within games. There are hundreds of judgment calls in every game. The official on the play, he viewed it, and he didn't view it as a penalty at the time," Walkom said.

But the officiating, and the change in its focus, has become a dominant story as the series has continued.

The Bruins were given 14 power plays in the first three games of the series, winning two of them. After Game 3, St. Louis Blues coach Craig Berube worked the refs, apparently to great effect.

"We were the least penalized team in the league in the first three rounds, now all of a sudden we've taken 14 penalties in one series. So, I don't know. I don't buy into all of that, to be honest with you," Berube said. "I think that we could definitely be more composed after the whistle. I think we've let some frustration get in there where we maybe do too much after the whistle. So we'll clean that up, for sure. But like I said, we were the least penalized team in the league coming into this series. I don't agree with all of the calls."

In Game 4, the Bruins received two power plays. "[Berube made] a comment to the refs about them being this angelic team, about not taking penalties all playoffs, and all of a sudden the whistles are put away," Bruins center David Backes said after that game.

Boston's Noel Acciari, left, battles with St. Louis' Tyler Bozak during the first period of Game 5 of the Stanley Cup Final on Thursday night in Boston. Dave Sandford/NHLI/Getty Images

In Game 5, the Bruins received three power plays, including one for a delay-of-game penalty on the Blues. They failed to convert on all three, although Jake DeBrusk's goal did come on a delayed penalty call in the third period.

Cassidy says he believes the way the series has been officiated changed after Berube spoke up.

"I sat here two days ago, or whatever it was, and said I believe these officials are at this level because they've earned the right to be here," Cassidy said. "You should be getting the best. But, I mean, the narrative changed after Game 3. There's a complaint or whatever put forth by the opposition. It just seems to have changed everything."

Berube denied this was the case.

"That my comments changed ... I don't agree with it, but it doesn't matter. I'm not here to judge the officials and calls that could have been or couldn't have," Berube said. "They go both ways. There were calls the other way that could have been called, and they weren't. So, I don't know what to say about that. I really don't want to say anything about it."

For the series, the Blues have been whistled for 23 penalties for 46 penalty minutes. The Bruins have 17 penalties for 36 penalty minutes.

The Bruins said they felt there were missed calls by the officials on questionable hits. Bruins defenseman Brandon Carlo acknowledged that the officials were letting them play in Game 5.

2019 Stanley Cup playoffs Miss a game from the 2019 Stanley Cup playoffs? Want to experience a game again? Every playoff matchup is available for replay on ESPN+. Watch now »

"Yeah, for sure. But there are penalties that you do need to call," Carlo said.

Cassidy said the hits were the kind "they want to get out of the game, correct? That's what I hear a lot about. Clearly, they missed a couple tonight."

It has not been the most exemplary postseason for NHL officiating, as some glaring errors have cost longtime referees assignments later in the postseason.

The league apologized to the Vegas Golden Knights after their Game 7 loss to the San Jose Sharks, when the Knights were given an unwarranted five-minute major penalty that helped the Sharks rally for the victory. Veteran referees Eric Furlatt and Dan O'Halloran were not carried over to the following round.

In the Western Conference finals, a blatant hand pass was missed that allowed the Sharks to beat the Blues in overtime. Again, veteran referees Marc Joannette and Dan O'Rourke were not carried over to the Stanley Cup Final. The NHL is also missing one of its best officials, Wes McCauley, who was injured in the conference final.

In criticizing the performance of officials Kelly Sutherland and Steve Kozari in Game 5, Cassidy slammed the officiating in the Stanley Cup playoffs on the whole.

"This has happened. I'm a fan of the game. It's the National Hockey League's getting a black-eye with their officiating in these playoffs, and there's another one that's going to be talked about," Cassidy said. "I thought it was a great hockey game. That call, probably ... there's time, but it really made it difficult for us to get the win tonight. So I'm disappointed. So I guess to answer your original question, it was egregious. But we're moving on. We're getting ready for Game 6."