Ana Dabovic had 18 for the Sparks (10-17), who padded their cushion between themselves, idle Seattle (7-20) and the Stars (7-21), for the final playoff berth out of the Western Conference.
Lavender blocked a career-high five shots and played in her 132nd consecutive game, second all-time for Los Angeles. Parker had 12 rebounds and nine assists. The Sparks shot 54 percent from the field and dominated in the paint 52-28.
Kayla McBride scored 13 points and Dearica Hamby 10 for the Stars, losers of five straight.
Nneka Ogwumike, the Sparks' second-leading scorer, sat out for the third straight game with concussion-like symptoms.
Parker scored nine points in an 11-2 run for a 28-13 first-quarter lead. The Sparks led 43-24 at halftime and led by as many as 37.