Sandstrom was playing his first NHL game since Dec. 13. He had been recalled from a conditioning stint with Lehigh Valley of the American Hockey League on Friday.
"Ended up in between what I wanted to do so it was a real bad play on my part," Sandstrom said. "... I'm really disappointed with myself with that. So yeah, not the best performance in that situation."
Kevin Stenlund shot into an empty net with 27 seconds remaining for the 5-3 final.
Jonsson-Fjallby, who plays on the fourth line with Kuhlman and Stenlund, made it 1-0 at 4:53 of the first period when he redirected a shot by Brenden Dillon, who had two assists.
"We've got a lot of skill on this team, and we know in the room when we commit to defending and playing the right way, we're going to score enough goals this year to be able to offset that," Dillon said. "We committed to it for a good chunk of the game, enough to win tonight."
Connor gave the Jets a 2-0 lead at 6:14, finishing a 2-on-1 with Cole Perfetti.
Scheifele scored to make it 3-0 at 8:31 after Nikolaj Ehlers skated the puck behind Philadelphia's net and passed up to Blake Wheeler, who bumped the puck to Scheifele for a goal from the left circle.