Watch Now: Game 5 Highlights: Blues at Bruins (4:03)

The Bruins lost Game 5 by a single goal on home ice Thursday night in Boston, falling into a 3-2 series hole to the Blues in the Stanley Cup Final. It was a tough result, especially considering the goal that proved to be St. Louis' game-winner shouldn't have counted.

With the Blues up 1-0 halfway through the third period, Tyler Bozak committed what appeared to be a clear tripping penalty on Noel Acciari, sending the Bruins' forward crashing to the ice. Acciari remained prone and stunned on the playing surface for an extended period of time as play continued without a penalty call. Just a few seconds later, the Blues scored on a David Perron shot that trickled through Tuukka Rask, giving St. Louis a 2-0 lead.

Instead of getting a power play with a chance to jumpstart a struggling offense and tie the game, the Bruins were dealt a back-breaker.

The Bruins were understandably furious with the sequence, especially upon seeing the replay that clearly shows Bozak sweeping the leg on Acciari. Even the Blues forward seemed to be anticipating a penalty on the sequence, as he immediately turned around to plead with the referee before realizing he was in the clear.

Those in Boston's corner couldn't help but throw things in frustration as a result of the horrendous missed call. Fans tossed water bottles and towels onto the ice as they loudly protested the officiating, while team president Cam Neely elected to chuck his water bottle at a wall instead. 

Even the Bruins' official Twitter account, which doesn't typically bring a lot of brand personality, couldn't help but fire off a scathing tweet.

It was the latest in a long line of questionable and perplexing officiating rulings this NHL postseason, and this one came on the biggest stage. 

After the game, Bruins coach Bruce Cassidy said that the missed called was "egregious" and "a black eye" for the league.

The NHL's Head of Officiating, Stephen Walkom delivered a statement on the Bozak non-call. 

"We don't make comments on judgment calls within games," said Walkom. "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."

There were a few other questionable non-calls during Thursday's game, including a headshot that Blues forward Ivan Barbashev delivered on Marcus Johansson. Barbashev escaped that incident without being penalized but it was announced Friday that he was to have a hearing with the league's Department of Player Safety, meaning he could be in line for a suspension. 

A lot has been made about the way the series has been officiated, and both coaches have had plenty to say about it. After the Blues gave up four power play goals in a Game 3 loss, St. Louis coach Craig Berube aired some grievances about the way the series was being called, specifically that his team was being penalized too much.

"We were the least-penalized team in the league in the first three rounds and now all of a sudden we've taken 14 penalties in one series," Berube told reporters, per The Athletic's Jeremy Rutherford. "I don't agree with all the calls." 

Some people, Boston defenseman Torey Krug included, believe that Berube's comments actually impacted the way the officiating crew has approached the series and that the Blues have gotten more breaks in Games 4 and 5 because of his complaints. 

After Game 5, Berube disagreed with that assessment and said he's not in a place to cast judgement on the officiating. 

"My comments changed (things)?" Berube said. "I don't agree with it, but that doesn't matter. I'm not here to judge the officials and calls that could have been or couldn't have been. They go both ways. I mean, there's 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." 

You can't quite say that the Bruins lost Game 5 because of the officiating, especially given Boston's poor offensive showing, but there's no arguing that a very terrible mistake from the referees proved to be very costly for the Bruins, who now are one loss away from finishing as league runner-up.