The Dallas goalie stoned Radim Vrbata just over 30 seconds into the first period, and stared down a number of other great chances in the opening 20 minutes in the Stars' 2-0 victory.
"That's always huge when you are able to make a great first save," said Lehtonen, who made 27 stops to pick up his second shutout of the season. "That gave me lots of confidence and that carried later on in the game."
Dallas has been dreadful defensively this season, averaging an NHL-worst 3.52 goals against per game coming into Wednesday, but played a solid final 40 minutes to hand Vancouver its fifth straight loss.
"A lot of the time you point to your goaltender whether you win it or you lose it," said Stars head coach Lindy Ruff. "When you lose you often point at him and when you win it's the guy that's going to get the credit. He made a couple big saves when we came out a little bit flat and I thought that really picked the team up."
Dallas (12-13-5) has wobbled through the start of the season with losing streaks of seven, four and three games, but Lehtonen — who sports a .906 save percentage and a 2.97 GAA — hasn't been terrible. He's just been hung out to dry a lot of nights.
"There has been some rough games and some games I have not done a great job so it kind of goes hand in hand," said Lehtonen. "Some nights players make it really easy for me and some nights I have to make some great saves, but that's just part of the job."
Lehtonen said he's been guilty of trying to do too much at times and as a result, finds himself out of position in the crease.
"I think I should be more patient and play a more simple game when things get harder," he said. "I was able to do that today, always wait where they are shooting and then trust that I can be fast and make the saves and it worked out tonight. I just have to keep doing that."
The Stars answered Lehtonen's great first period on Wednesday with a much-improved effort, holding the Canucks to just four shots in the second.
"He gave us a fighting chance in the first period to win a hockey game and the second period we answered the bell by going after them pretty good," said Ruff. "We've been working hard playing defence in the offensive zone, controlling the puck and zone time. I thought we did a lot better job of that. We had some shifts that we totally finished in the offensive zone."
The Stars — with a potent offence lead by Tyler Seguin — aren't by any means out of the playoff picture in the Western Conference, but an improved defensive game will be key to them making a run at the post-season.
And so will a lot more nights like this one from Lehtonen.
"When you struggle and bad or tough goals go in it's hard," said Ruff. "The hope tank for the team goes down (but) when your goalie's playing great you think you can beat anybody.
"A counter punch off a big save is often one of the deadliest things in the game."