"We need to defend better," he said. "Part of that is intensity, urgency, pick your word, we didn't have it. You've got to manage the puck first, and then once you don't have it anymore, you've got to have a certain level of structure and urgency to get it back, and we didn't."
It resulted in forced plays, in slow transitions, in turnovers. And that turned into hockey that was undisciplined, ragged and out of control.
The Bruins got back into the game in the second period, when Bergeron scored on the power play at 14:12 to cut the lead to 2-1, and had chances to tie it but were thwarted by goaltender Andrei Vasilevskiy, Tampa Bay's defense and their own misplays.
"I think we looked slower than them," Cassidy said. "They are a fast team, so we expect them to play fast. I just think we're not supporting each other quick enough and then making the appropriate play with the puck to appear faster. It seems like it's getting turned over and coming back at us. All of a sudden you're chasing it all the time."
It started with a bobbled puck by defenseman Matt Grzelcyk, who tried to glove a high dump-in by Lightning defenseman Anton Stralman. Grzelcyk lost sight of the puck and got turned around, which allowed Tyler Johnson to send a pass across the slot to the waiting Palat at 1:47 for a 1-0 lead.
"Just trying to gap up, puck kind of felt like it back-spun on me on the ice," Grzelcyk said. "Thought maybe it went behind me, so just took my eye off the puck and they capitalized because they're a good team."