Chiasson said: "It makes a big difference when you score, and then you score again. That usually kills the other team's momentum. I thought that changed the game right there."
Flames coach Bob Hartley agreed.
"Those three quick goals, they definitely took lots of energy out of us and we just couldn't recover."
Lehtonen, returning after five games on injured reserve because of a leg injury, appreciated the offensive support.
"It was good that we got those goals. That made it easier to relax," he said.
Dallas had lost four of the five games while Lehtonen was out. Against Calgary, he made 28 saves.
On Thursday, the Flames completed a five-game trip on which they were 1-4.
"We're not quitters over here but it's a results-oriented business and it was a terrible road trip," Calgary left wing T.J. Gagliardi said. "We just had breakdowns and off-man rushes. They're skilled enough where they're going to make you pay."
Dallas (4-5) dominated the early going, with the game's first four shots on goal. Two of those were by Chiasson.
Ramo stopped the first from in front of the goal, but Chiasson retrieved the puck and tapped it in for a 1-0 at 4:04 of the first period.
"The first goal by Chaser was real good hands on his part," Ruff said. "The play from Whitney was a real nice opportunity."
The Flames (4-4-2) tied the game 4:30 into the second period. Lee Stempniak skated along the right wing. Defenseman Trevor Daley stayed with a Flame across the ice and when center Cody Eakin skated from behind Stempniak, he shot the puck past Lehtonen.
Chiasson had a chance for a third goal late in the second period from the left circle, but Ramo deflected the puck wide of the net.
Benn scored again at 3:36 of the third period. A missed shot went off the back boards. Chiasson picked up the puck and slid it behind the goal to Benn. His wraparound shot beat Ramo.
Hartley said: "I felt that we started the third period on a good note. We had a huge hole to come back and they got that goal, so basically the game was over right there."
Ruff was asked if the Stars were trying to get a hat trick for Chiasson or Benn.
"I think the players were. Every puck was getting funneled in one direction. When you've got that lead at that time of the game, you're looking for something good like that."
Dallas twice in the third period failed to score on 5-on-3 advantages against a Flames penalty-killing unit that ranked last in the NHL.
Dallas defenseman Kevin Connauton made his NHL debut. He was on the ice for the first goal, and was penalized for holding at 16:41 of the first period. He later blocked four shots ... Stars forward Ryan Garbutt served the first game of a five-game suspension for charging Anaheim's Dustin Penner Sunday ... Calgary center Matt Stajan also returned from a leg injury that had kept him out since Oct. 3. He assisted on the Flames' goal. ... In his second NHL game, Calgary defenseman Christopher Breen drew a 5-minute penalty for fighting with Dallas' Lane MacDermid.
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DALLAS, TX - OCTOBER 24: Jamie Benn #14 of the Dallas Stars handles the puck against TJ Brodie #7 of the Calgary...