BOSTON -- Boston Bruins coach Bruce Cassidy was still upset over the state of officiating in the Stanley Cup playoffs on the day after the team's Game 5 loss to the St. Louis Blues, but he said it's time to pivot to a win-or-go-home game on Sunday.

"Today's a new day. So we're going to move forward and get ready for Game 6. That's what's in front of us," he said at the Bruins' practice facility.

At issue in Game 5 was a missed tripping penalty on Blues center Tyler Bozak that took Boston forward Noel Acciari out of the play -- and into the concussion protocol -- moments before David Perron scored what would be the game-winning goal for the Blues.

Cassidy also was critical of the officials for not penalizing hits he felt crossed the line, and the NHL agreed on at least one of them: Blues forward Ivan Barbashev has a hearing with the Department of Players Safety for his hit on Marcus Johansson. The NHL tells ESPN that there's no supplemental discipline for Bozak, despite belief from Boston loyalists that there was a slew foot on the play.

Cassidy also claimed that the Blues were getting the benefit of the officiating after coach Craig Berube's comments after Game 3, in which he wondered how "the least penalized team in the playoffs" could suddenly give the Bruins 14 power plays in three games in the Stanley Cup Final. Berube denied that was the case after Game 5.

But in his postgame comments, Cassidy went beyond criticism of the on-ice officials in the series and expanded it to include the officiating in the playoffs as a whole, calling its quality a "black eye" for the NHL.

"I think I was pretty honest about it yesterday. My feeling hasn't changed. I feel it was a missed call that impacted the game, unfortunately in a negative way for us. Other than that, we talked about how there's been a few in the postseason, because I'm a fan of the game," Cassidy said.

"For me, it's a privilege and an honor to be working in the National Hockey League and in the Final. I'd rather be talking about -- we're ambassadors of the game, too. We want to grow the game. We're miked up, we're trying to give them access, so I'm all for that. That's what we're trying to do. I'd rather be talking about that than a missed call that affects the game. That's how it was last night."

Cassidy said that he doesn't expect his team to let the blown call linger ahead of Game 6 in St. Louis on Sunday.

"Our play should define us, not the call," he said.

"Let's go back to Toronto [in the first round]. We lost Game 5 at home. There was a review on the [Auston] Matthews goal. Some people felt it was goalie interference, some people didn't. We had to go to Toronto and put that behind us. We went to Columbus [in Round 2] and had one off the netting that ended up in our net. So we played through certain situations, and we have to play through this one. I actually thought we responded fairly well. We got ourselves back in the game, cut the deficit to 2-1 and got a chance to win. But our play has to define us on the ice, not a non-call or a call or whatever."