Jenny Boucek won in her coaching debut for the Storm. She took over in January after Brian Agler left to coach the Sparks.
In front of a sell-out crowd at Key Arena, Seattle also opened the season with a victory for the first time since 2010 and beat the Sparks for the first time in their last six meetings.
Sue Bird and Alysha Clark each scored 11 points, and the Storm shot 51.6 percent from the field (33 of 64), including 9 of 20 from long range. Seattle outscored LA 34-16 in the paint.
Rookie Jewell Loyd, the No. 1 overall pick, started and scored seven points on 2-for-10 shooting.
The Sparks were without four of their top five scorers from a year ago, including leading scorer Candace Parker, Kristi Tolliver and 2012 Rookie of the Year Nneka Ogwumike. Alana Beard led Los Angeles with 20 points. Erin Phillips had 11, and Jantel Lavender 10.
The Storm made six 3-pointers in the fourth quarter to turn the game into a rout.