Boston Bruins head coach Bruce Cassidy vented his frustration after another controversial non-call took the spotlight during his team's Game 5 loss to the St. Louis Blues in the Stanley Cup Final.

"I’m a fan of the game," Cassidy said, according to ESPN's Greg Wyshynski. "It’s the National Hockey League getting a black eye with their officiating in these playoffs, and there’s another one that’s going to be talked about."

With less than 10 minutes to play in the third period and St. Louis holding a 1-0 advantage, Tyler Bozak seemingly tripped Bruins forward Noel Acciari in Boston's zone. The play allowed David Perron to pick up the puck and beat netminder Tuukka Rask with a bank shot.

"The no-call on Acciari ... their player is on his way to the box," Cassidy said. "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."

The Bruins bench boss also wasn't happy with a couple of hits that he perceived to be illegal checks to the head.

"Those are the hits they want to get out of the game, correct? That's what I hear a lot about," he said. "Clearly, they missed a couple tonight. It's a fast game. 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 believes the series took a turn when Blues head coach Craig Berube complained about the officiating after Game 3.

"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," he said.

Officials have been held under a microscope all postseason after multiple botched calls.

In Game 7 of the opening-round series between the San Jose Sharks and Vegas Golden Knights, a questionable five-minute major allowed the Sharks to erase a 3-0 deficit and win the game in overtime. The Blues found themselves on the opposite side of a controversial play in Western Conference Final when the Sharks scored the overtime winner in Game 3 courtesy of a hand pass.

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