Mrazek made 15 saves in the second period and 17 saves in the third period.
"He's a battler," Blackhawks coach Luke Richardson said. "He works hard. And there's been so many games this year ... we haven't gotten a lot of goal support when he's played well and kept us in the game. It's really nice to see a guy get rewarded in that way. You can't go out and score goals, so we've got to get a few for him to have success in the net."
Frost made it 1-0 at 8:52 of the first period. Nick Seeler took advantage of a turnover in the defensive zone and passed to Frost, who crossed the Chicago blue line, deked Jones to create space for himself and beat Mrazek over his glove.
Toews tied it at 9:51 of the second when he skated into the slot and tipped Jones' shot from the right point over Hart's right shoulder.
"High tip and a screen," Hart said. "Didn't really see the release. Just tried to get my body in front, and he makes a pretty good tip under the bar."
Reese Johnson made it 2-1 at 15:51. Flyers forward Owen Tippett turned the puck over at the Philadelphia blue line, and Blackwell centered it to Johnson, who scored from the slot.
Tyler Johnson scored on the rebound of a Patrick Kane shot 35 seconds into the third period to make it 3-1.
"The first shift [of the third] basically kind of dictated the way we're going to play the rest of the way," Richardson said. "It was a great goal by 'Kaner' shooting that puck and Tyler stripping it in the neutral zone and then finishing off at the net. I think it took some life out of them and it gave us some life. So, I think that was a big key to the game."