McAvoy, whose thunderous neutral-zone hit on Florida's Eetu Luostarinen helped turn the momentum earlier in the third period, admitted that the power-play marker - his first goal of the season - wasn't quite how the Bruins drew it up.
"You know, it was funny, cause that's not really how we script it," said McAvoy, who led the Bruins in ice time with 24:51. "I said it right after. A lot of the things Butchy talks about is just possession over position, so we get the puck and we're trying to make plays and that's kind of where skill takes over. I don't really know what I'm doing there backdoor. But that's kinda where I ended up.
"Marchy's on that side. I'm on this side. [David Pastrnak's] on the top. But that's kind of where we just trust each other, and I guess you want to let the skill take over. It was really nice to see that one go in.
"We've been working really hard. I don't really think we've been getting rewarded too much so that was nice our resilience came through tonight."
Cassidy had been displeased with the pace of Boston's power play, noting earlier on Saturday that the B's were moving too slowly, thus becoming too predictable to the opponent. That changed on Boston's tying tally as they moved the puck quickly and struck just 18 seconds after Carter Verhaeghe went to the box for hooking Craig Smith.
"One of the things [Cassidy] said was trying to just get moving when they're pressuring like that versus the stationary look," McAvoy explained. "I think what kinda happens there is Marchy gets it, he starts attacking, he's just moving, we're trying to move, a lane opens up, and then it's in the back of the net.
"But I think I tend to make better plays when I'm moving, when I'm sort of just feeling the flow. I have my head up. I think a lot of people feel that way and I was kind of proud of what happened there."