Voracek had a goal and three assists for the second straight game. He's the first Flyers player with back-to-back four-point games since Eric Lindros on Dec. 31, 1997 and Jan. 3, 1998.
Steve Mason made 21 saves for Philadelphia (17-10-3), which has won eight straight for the first time since Jan. 6-19, 2002.
Devin Shore had his first two-goal game for Dallas (11-12-6). Lehtonen made 18 saves.
Shore's second goal put the Stars ahead 2-1 at 10:32 of the third period, but two penalties later in the period proved costly. Defenseman Jamie Oleksiak was called for cross-checking at 15:06, and center Tyler Seguin for high-sticking at 17:03.
"We played a good game 5-on-5 and lost it with untimely penalties," Seguin said. "I had a bad penalty there. You could say they had a couple of good looks on the power play or we have to find a way to be better on the kill."
Voracek closed the scoring with an empty-net goal. He has 15 points (four goals, 11 assists) in his past eight games.
"I don't think I've changed my game," Voracek said. "Even if I went those six games without a point, from a couple weeks back I don't think I'm playing any different now. When you stick with it and work hard, the points eventually are going to come. That's exactly what's happening now."
Shore put the Stars ahead 1-0 at 7:30 of the first period, and gave them a 2-1 lead in the third when he pushed a puck under Mason and inside the right post.