The Stars had given up 14 goals in losing back-to-back games, but settled down on defense to defeat the Oilers for the third time in 15 days.
Adam Burish opened the scoring for Dallas midway through the first period and Morrow then produced his 20th and 21st goals of the season during the second. Jamie Langenbrunner assisted on both the Morrow goals.
Dustin Penner delivered a power-play goal for the Oilers with 2:26 to go in the second and Lehtonen stopped all 11 shots he saw in the third. The Stars have won seven of their last 10 and will go into the all-star break with a five-point lead over Anaheim at the top of the Pacific Division.
Edmonton has lost six out of seven. Nikolai Khabibulin suffered the setback, allowing three goals on 21 shots.