BOSTON — Bruce Cassidy needs to see more from the Bruins defense.

Boston suffered a 3-2 overtime loss Thursday night at the hands of the Philadelphia Flyers at TD Garden. The Flyers now are winners of six straight, but sit in seventh place in the Metropolitan Division. The B’s have struggled to find their rhythm, losing five of their last six after starting the month a perfect 4-0-0, and Boston’s boss bench called for more urgency from his defense and his captain, Zdeno Chara.

“He’s the captain of the hockey club … he won a Stanley Cup here by being a defensive stalwart, one of the best penalty killers in the league,” Cassidy said after the game. “So, yes, he’s part of that group, and the biggest part of it. He’s a terrific leader that the next game he understands what makes us successful. … He is the leader back there. He’s gotta get Charlie (McAvoy) to buy in, gotta get (Brandon) Carlo, Kevan Miller, put him in that group too. They have to lead back there and understand what it takes to be successful right now for us. Right now for us is team defense, good special teams. And hopefully get some secondary scoring when the top line’s not on.”

The top line, as it has often this season, turned in another multi-point game. David Pastrnak tallied Boston’s two goals while Patrice Bergeron and Brad Marchand each picked up an assist. So while they remain consistent, the forwards as a whole also need to step up a little bit in one facet, as well as the defense.

“There’s the first problem, right? Part of our D corps doesn’t have numbers because we don’t hit the net very often,” Cassidy said. “So there’s an issue right there. Now, are you gonna get mad at every player that misses the net every time? Of course not. But after two periods I think Philly had missed the net once. So that’s partly on us. That is on the player to hit the net.”

Here are some other notes from Thursday’s Bruins-Flyers game:

— Patrnak’s second-period goal marked his 30th of the season. This is the third consecutive season the 22-year-old has at least 30 tallies in a season.

He leads the league in power-play goals with 15.

— Thursday marked David Backes’ 900th NHL game, while Brandon Carlo was playing in his 200th.

— Despite a frustrating loss, Backes is ready to put the tough stretch behind him and start Super Bowl Sunday on a high note for Boston fans.

“What an opportunity to to exorcise some demons and get a win, get back on track,” Backes said, “and beat a team that we’re due to beat and squash all those things at once. Take care of business first, and then be able to watch our home team in the Super Bowl after that.”

— Tuukka Rask played in his first game since sustaining a concussion Jan. 19 against the New York Rangers, stopping 38 shots. He still remains tied with Tiny Thompson for most wins in Bruins history, but Cassidy was encouraged by his performance.

“I thought Tuukka was terrific,” Cassidy said. “Gave us every chance to win the game. It didn’t work out for us in that regard, in terms of generating enough goals for him, but no issues with Tuukka at all.”

Thumbnail photo via Bob DeChiara/USA TODAY Sports Images