Defenseman Jake McCabe said he felt the tide begin to turn after van Riemsdyk's goal made it 2-0.
"That was when I was more disappointed than anything because our response after that was we came into our shell and gave them way too much time and space the rest of the game for them to make plays," he said.
The Flyers began another barrage at 8:20 of the third, this time when Provorov delivered a shot from the point through traffic on the power play. Pitlick later tapped his own rebound in off the stick of Henri Jokiharju, then van Riemsdyk's power-play goal deflected in off the skate of Rasmus Ristolainen.
Philadelphia finished the night 3-for-5 on the power play.
"The puck seemed to be bouncing in some strange directions but we also lost position a few times," Krueger said. "When Larsson went down, with arguably two centermen out that are important in our game plan, I thought the guys tried to fill in there but it seemed like chances were going in too quickly on us.
"Again, there's not much really pretty that I can say about this whole situation. We got slapped hard today. They played very, very well and saw the opportunity and took it and we have to be angry about it, but use that anger for energy in the right way and that's what we'll do."
The Sabres will practice at home on Friday, then have two more games before the Christmas break. The first is against Los Angeles at KeyBank Center on Saturday afternoon.
"It's over. It's done and over with," Kyle Okposo said. "Obviously, you feel bad about it tonight, but we've got the Kings coming into our building on Saturday and that's it. It's one game, you move on, come to work tomorrow, you get better, and I promise you we won't come out like that on Saturday."