The Boston Bruins fell 4-3 to the Florida Panthers at the TD Garden on Monday as a heated game led to undisciplined hockey and the B’s second loss in a week.

It was another mental and physical game for the Bruins as the B’s struggled to figure out the Panthers and let them get under their skin.

“They’re winning the mental side of the battle against us,” Jim Montgomery said.

“And we can’t lose that many puck battles,” he added. “They are the standard in the NHL for winning battles and we are not reaching that level.”

Here are the highlights of the game:

First period:

Mark Kastelic put a shot on net that deflected off Johnny Beecher off Sergei Bobrovsky’s five-hole at 4:53 of the first period. 1-0 Bruins.

Anton Lundell stuffed one past Jeremy Swayman’s left skate and the post to get Florida on the board at 6:37 of the first period. 1-1 match.

Things started to get heated after AJ Greer hit David Pastrnak from behind, causing Pavel Zacha to drop the gloves with him. Shortly afterwards, Charlie McAvoy went to the box for cross-checking. Five seconds into their power play, Sam Reinhart beat Swayman’s blocker with a wrist shot at 11:51 of the first period. 2-1 Panthers.

Second period:

Brandon Carlo tied the game by putting a long wrist shot from the top of the right circle past Bobrovsky at 5:08 of the second period. 2-2 game.

A few minutes later, Pastrnak tried to poke the puck past Bobrovsky on the power play but came up short. Off the rush, Florida came off the other ice and with a short hand, Reinhart found the loose puck on Jesper Boqvist’s attempt at 9:39 of the second period. 3-2 Panthers.

Lundell then found a gap between Swayman’s pad and blocker after unleashing a wrist shot from the right circle at 12:59 of the second period. 4-2 Panthers.

The Bruins bounced back when Mason Lohrei walked into the left circle after receiving a heads-up pass from Kastelic and sent a wrist shot past Bobrovsky’s stick at 14:07 of the second period. 4-3 game.

Third period:

No goals

Final score: 4-3 Panthers

Game notes

• If there is a silver lining, it is the bottom six forwards and more specifically the play of the fourth line. Kastelic, Beecher and Koepke have really built good chemistry and defined their roles over the last four games. Beecher said after the game that they all have the same playing style and they just stick to playing to their strengths.
• Jim Montgomery said after the game, “They’re just doing their role. Guys in the top six are not fulfilling their roles.” He was “impressed” by the play of the fourth line as they had a hand in every goal this afternoon. Brad Marchand agreed: “The rest of us need to take a page out of our book and be a lot better,” Marchand said. “They’re definitely carrying the weight right now.”
• Kastelic assisted on every goal, with two primary assists. His shot hit Beecher just enough to be credited. Kastelic’s pass to Lohrei was also so well timed and set up for the third goal.
• Lohrei also continued to find his form and registered a goal and assist tonight.
• The Bruins still lack consistent production from their top guys. The fourth line contributed to every goal, two of which were scored by Bruins defensemen. Although only four games have been played, you’d like to see a little more production from guys like Charlie Coyle and Morgan Geekie (who is yet to record a point in four games) on the scoresheet.
• It was also another night without a power play goal, as the Bruins were 0 to 4 on the man advantage.
• The Bruins struggled to sustain offensive zone time and get clean access to the ozone to really keep the coverage going there. And when other teams target Pastrnak, like today, the guys defending him end up being taken out of the mix. Marchand dropped the gloves twice today, calling for roughing both times and Zacha finishing with a fighting major.
• I said it before, but the penalties are piling up. The Bruins have committed five or more penalties in every game this season. It wasn’t the reactions to defend Pastrnak that were the problem tonight – as Pavel Zacha and Brad Marchand both stepped up during the heated match, but the penalties like Charlie McAvoy’s immediately afterwards ultimately cost them.
• “I love what Pav did and defended him (Pastrnak), but the penalties after that? That’s just not disciplined,” Montgomery said. “It is four games in which we have played at least four minors. You can’t win hockey games that way.”
• Lundell and Reinhart each scored twice for the Panthers, who played without Aleksander Barkov and Matthew Tkachuk due to injury and illness.
• The Bruins travel to Colorado to face the Avalanche on Wednesday, October 16, for a 9:30 PM ET start time.