Lehtinen notched his 21st goal from the left circle with five seconds remaining on a tripping penalty against Lukas Krajicek. That completed the Stars' rally and improved their mark to 12-3-2 in the last 17 games.
Roberto Luongo was less than 30 seconds away from his 31st NHL shutout when the Stars tied it at one on Philippe Boucher's power-play goal. The Stars went on a two-man advantage with 1:50 left, and had a six-on-three skating edge with 1:05 remaining when goalie Marty Turco was pulled for an extra attacker.
Dallas still had a one-man power play when Boucher scored with 28.3 seconds left, registering his 17th goal of the season from the slot after a setup by Mike Ribeiro.
Taylor Pyatt had a second-period goal for the Canucks, who had won each of their previous six games by one goal.
Turco made 17 saves as the Stars improved to 8-1-1 in their last 10 home games.
With 77 points, Dallas pulled into a second-place tie with San Jose in the Pacific Division. The Canucks also have 77 points and hold a two-point lead atop the Northwest over Minnesota.
Luongo, who had won 10 of his previous 11 road starts, finished with 34 saves.
Stars backup goalie Mike Smith had played in four of Dallas' previous seven games, including three starts, as coach Dave Tippett gave Turco some rest. Smith had been 4-1 with a 1.15 goals-against average in his last five starts, but Tippett wanted to get his No. 1 goalie back in the nets. Turco rewarded that confidence with his 28th victory of the season.
Pyatt gave the Canucks the lead at 10:17 of the second period with his 17th goal after taking possession of a loose puck in the slot.
Luongo had some luck on his side when a power-play slap shot by Dallas' Darryl Sydor clanged off the right post with just under 12 minutes remaining in regulation.
Notes: Vancouver D Mattias Ohlund had the flu and couldn't play after the first period. ... Dallas C Eric Lindros missed his sixth consecutive game. Lindros is recovering from the flu and an undisclosed lower-body injury. ... Turco is 13-2-1 against Vancouver. ... Dallas has won six straight at home against the Canucks.