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.
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