Lehtonen stopped 28 shots and Brad Richards scored the go-ahead goal at 6:32 of the third period to lead the Stars to a 4-2 victory over the St. Louis Blues on Sunday.
Lehtonen broke a four-game losing streak, and improved to 6-1 lifetime against St. Louis. Lehtonen has never allowed more than two goals in all seven career starts against the Blues.
"I don't know if there's any secret to it," he said. "I just try to come in here and play well. It certainly wasn't easy."
Lehtonen, who improved to 16-10-4, stopped the final 19 shots. He had given up 10 goals in his previous two games.
"It was a great bounce-back game for him," Dallas coach Marc Crawford said. "They had a couple really good chances in the third period and he stood his ground. He's a calming influence when he plays like that."
Lehtonen helped the Stars to their fifth successive road victory. They are 0-3-1 in their last four home games.
"It would be nice to be good at both places," Lehtonen said.
Richards had two assists and Brenden Morrow scored twice to help Dallas finish 4-0 against St. Louis this season. Dallas outscored St. Louis 7-0 in the third period during the four contests and won the first three meetings by one goal.
"A win is a win, they are all important," Morrow said. "But the way we're doing it gives us a lot of confidence."
James Neal added a goal with 2:50 left.
St. Louis, which carried a 2-1 lead into the third period, had a five-game winning streak snapped. Alex Steen and David Backes scored for the Blues. Steen has a team-high 13 goals, nine in the last 16 games.
The Blues were 12-2-1 when leading after two periods.
"They started making us pay in the third period," Backes said. "We needed a little more push, a little more effort."
Morrow began the comeback with his second goal of night 2:28 into the third period. Richards added his team-high 18th goal and his third game-winning tally of the season.
"It was a real good finish," Richards said. "Huge. You have to take the two points when you can get them."
The Blues, who had won their last four home games, fell to a 14-5-2 at home.
"We had an opportunity to steal a game we probably didn't deserve," said St. Louis defenseman Barret Jackman. "We just weren't able to do it."
NOTES: Dallas last won five straight road games Jan. 17-Feb. 7, 2008. ... The contest featured a 1:15 brawl between St. Louis' Cam Janssen and Dallas' Krystofer Barch in the opening period. "I've got no feelings for him, we're always trying to kill each other," Barch said... The Blues have 37 fighting majors this season -- third in the NHL. ... The Blues have sold out all 21 of their home games. ... The Blues had a seven-game winning streak earlier in the season from Oct. 22 to Nov. 7.