Henrik Sedin's second-period goal was waved off for "incidental contact" on Lehtonen and the Canucks' scoring struggles continued in a 2-1 loss to Dallas on Sunday.
Down 1-0 after the first, Vancouver looked to have tied the score at 6:42 of the second when Vancouver's captain beat Lehtonen upstairs from a sharp angle on a power play.
But the celebrations were short-lived after officials deemed that Daniel Sedin had interfered with Lehtonen.
Television replays appeared to show no contact between the two players, which left both the crowd at Rogers Arena and Canucks coach John Tortorella incensed.
"It's a bad call. It's a made-up call," Henrik Sedin said. "If it's a 50-50 call, then I buy it. If it's a 40-60, I buy it. Even a 20-80 (call) ... tough to take."
Tortorella said he never got an explanation, but added that the NHL needs to change how it reviews goals.
"I'm not going to whine about this and that. It's a huge call that was the wrong call, but doesn't determine the winning and losing of the hockey game," said Tortorella, whose team has scored just four goals in losing four straight. "If you don't see it, don't call it.
"You have to be sure on that play and I just don't think they were sure. It was the wrong call."
Added Daniel Sedin: "It's tough, but the chances we had today, we have to score more than one goal. That shouldn't be the difference."
Lehtonen, who was brilliant in a 42-save performance against the Canucks, was surprised the goal was waved off.
"It happens so fast," he said. "I wish they would maybe use some video replay or something just to make (the calls) right."
Henrik Sedin scored in the third period for Vancouver (11-8-3), which got 21 saves from Roberto Luongo as the Canucks fell to 4-4-1 at home.
"You've just got to play. That's the bottom line," Luongo said. "Sometimes things go your way, sometimes they don't, but you can't let that stuff affect you in a negative way on the ice."
After Lehtonen held off the Canucks in a second period that saw Vancouver hold a 20-6 edge in shots, Cole made it 2-0 early in the third. Henrik Sedin made a bad decision to step up at the Stars' blue line while covering for a pinching Kevin Bieksa, with Cole scoring his second of the season at 1:42 on the resulting 2-on-1 break.
Henrik Sedin got Vancouver on the scoreboard at 3:06 of the third when he chipped a shot over Lehtonen with the Canucks on the power play for his fourth of the season.
Vancouver made a late push, but Lehtonen wasn't really troubled much the rest of the way in recording his 10th win of the season as the Canucks mustered 10 shots in the final period.
"We're professionals. We've got to start burying those chances. Really, enough's enough," said Canucks forward Ryan Kesler, who played his 600th career game. "We have to bear down and not get frustrated, but we have to capitalize. That's on us."
The Canucks' 28th-ranked power play had another chance on the same man advantage after the disallowed goal in the second period, but Lehtonen made a great stop on Bieksa.
Canucks forward Alexandre Burrows then redirected a pass from Henrik Sedin that beat Lehtonon but not the post as Vancouver led 33-13 on the shot clock after 40 minutes.
"We've done it a couple different ways on this road trip," Cole said. "Kari was great for us tonight. You could tell he had great focus and was on his game, and really weathered the storm in the second period.
"He's been fantastic. Night after night he continues to surprise even us making unbelievable saves."
Another bright spot for the Stars has been their top line, which continued their recent hot streak when Nichushkin opened the scoring at 9:33 of the first period. Jamie Benn worked the puck behind the net to Tyler Seguin, who in turn passed to the 18-year-old Russian on Luongo's doorstep for his second of the season.
Seguin had four goals and an assist against Calgary on Thursday, Benn finished with a goal and five assists, and Nichushkin picked up two assists.
"They have been real good," Stars coach Lindy Ruff said. "They had a couple really good opportunities they didn't convert on, but we know it isn't going to keep going at this pace. I hope it does, but it probably won't."
Vancouver, which was coming off a 2-1 overtime loss to the San Jose Sharks on Thursday, nearly grabbed an early lead on a Henrik Sedin breakaway that was stopped by Lehtonen less than a minute in.
"I thought our team played hard," Tortorella said. "We just need to stay within ourselves and keep on playing and not get frustrated and not let it get to us.
"It's not about blowing things up, it's a matter of staying with it."
Seguin has points in four straight games (six goals, two assists). ... Benn was the first Stars player to record six points in game since Mike Modano had two goals and four assists on Feb. 1, 1995. ... Canucks forward Jannik Hansen returned to the lineup after missing 10 games with an upper-body injury. ... Canucks forward Ryan Kesler and Stars forward Vernon Fiddler both played their 600th career game. ... The Canucks host the Florida Panthers on Tuesday, while the Stars welcome the New York Rangers on Thursday.