Boston fell to 4-5-1 as it failed to consistently generate quality chances against a Philadelphia club that was conceding nearly 4.5 goals per game, second-worst in the NHL.

The good news was that the Bruins stayed out of the penalty box for the first twenty minutes. The downside is that they also stayed off the scoresheet.

Joonas Korpisalo shined early and late as the Boston goalkeeper made his first start in almost two weeks.

Korpisalo made back-to-back saves on Philadelphia winger Bobby Brink, first fending one off with the blocker and then smothering the follow-up play with his right pad.

It was part of a mini-Flyers surge made possible by heavy checks that kept defensemen Charlie McAvoy and Mason Lohrei on the ice for an extended shift.

Just when it looked like Philly goalie Samuel Ersson wouldn’t break a sweat, Cole Koepke woke him up with a shot off the facemask from the blue line.

Boston put together some nice offense on a five-on-three power play when Scott Laughton cross-checked Brad Marchand and 23 seconds later Travis Sanheim tagged David Pastrnak.

The Bruins were effective and Marchand had the best chance but was denied by Ersson.

The power play save came from Korpisalo, who grabbed a Garnet Hathaway wrister from a two-on-one from Laughton, who had just emerged from the box.

Ersson denied Pavel Zacha (nice feed from Matt Poitras) and Elias Lindholm (outright dish from Andrew Peeke), and Peeke sent a screamer from the far post to end the period.

Korpisalo matched several Class A stops, including denying Ryan Poehling a partial burglary.

Rasmus Ristolainen, last seen injuring Poitras with a big hit at the buzzer of a preseason game, tried to get the Flyers off to a flying start with a riser from the blue line, but Korpisalo gobbled it up.

Pastrnak temporarily eliminated Jamie Drysdale with a rocket just inside the blue line that hit the Flyers defenseman in the abdomen. The Bruins peppered Ersson for more than 30 seconds as Drysdale tried to get to his feet.

He eventually reached the bank and walked through the tunnel before returning a few shifts later.

Philadelphia broke the ice when an unmarked Tyson Foerster broke a low wrister through Korpisalo’s five-hole.

The Flyers went on the power play seconds later (Koepke for heels) but couldn’t dent Korpisalo and extend their lead.

Boston got another chance on the power play when Morgan Frost got Morgan Geekie in the chop with a high stick. Despite having plenty of zone time, the Bruins had zero shots with the man advantage and went into the locker room trailing 1-0 after 40 minutes.

Jim McBride can be reached at [email protected]. Follow him @globejimmcbride.