Lehtonen's whitewash was his fourth of the season for the Stars, whose late-season surge reached 11 games in which they have gained at least one point (10-0-1).
Jamie Benn collected the game's only goal for Dallas, which remained without a regulation loss since a 3-2 setback Feb. 19 against Nashville.
Matt Hackett took the hard-luck loss, turning aside 24-of-25 shots for the Wild, which fell for the seventh time in eight games.
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend
Pregnant Mila Kunis wins 'Best Villain' at MTV Movie Awards