PHILADELPHIA — Chicago's defense at Xfinity Mobile Arena this week left much to be desired.

On Wednesday, the Bulls' 157-137 loss to the 76ers marked the most points they've allowed in a regulation game since March 1969.

Then on Thursday, the Blackhawks got skated out of the same building in a 5-1 loss to the Flyers.

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"We didn't have enough guys close to their best," Hawks coach Jeff Blashill said. "It's a hard league when you don't have that. It's part of what we're learning, how to have your 'A' [game] and then your 'B-plus' game."

The Hawks allowed more than 40 shots on goal for the third time in four games. Some sudden cracks in their structure are starting to erode.

The only silver lining was that Louis Crevier, whose cheek was sliced open by a Flyers skate blade in the third period, turned out to be OK after great initial concern.

A miscommunication between Spencer Knight and Artyom Levshunov that led to a Flyers empty-net goal in the first minute set the off-key tone for the Hawks, who produced arguably their second-most unfocused, undisciplined and error-prone performance this season.

The only memorably worse game was the late-January visit to Pittsburgh. The state of Pennsylvania was quite unwelcoming this season.

"[The Flyers] played more intense than us," Connor Bedard said. "I thought we didn’t really match that, for whatever reason. Obviously [it's] something we got to do better."

Indeed, there has been a noticeable contrast in urgency levels between the out-of-contention Hawks and their last three opponents, who all happen to be clawing for their lives on the playoff bubbles. The Hawks haven't been decisive enough when gathering pucks or fighting for them in battles.

"We have a lot of importance in these last [10] games, whether it’s for the playoffs or not," Bedard added. "We’re tired of being in the spot we’re in [in] April."

Young Hawks defensemen made poor decisions to step up in the neutral zone all night long, allowing a steady stream of odd-man