"For me, it's do whatever I can do to help the team," Simmonds said. "Whether I'm scoring or not scoring, I've got to be doing something on a nightly basis that's helping us get the two points."
Carlson scored on a backhand from the left face-off circle at 16:07 to make it 5-3.
Voracek made it 6-3 with an empty-net goal with 38 seconds remaining.
Washington leads Pittsburgh by two points for first in the Metropolitan, but forward Jay Beagle said the Capitals need to be more aggressive.
"We have to start playing playoff hockey," he said. "You have to start right now. Teams that are fighting for spots and teams that are a little more desperate, we have to match how desperate they are and we have to go after them rather than sitting back and waiting for the game to come to us. … We've got to learn from this and make sure we don't let it happen again, especially going into these last 10."
Gostisbehere scored on a one-timer at 2:15 of the second to give the Flyers a 1-0 lead.
Ovechkin tied it 1-1 at 15:08 when he tipped Travis Boyd's shot past Mrazek. It was his 601st NHL goal, tying Jari Kurri for 19th all time.