Rubio Rubin had a pair of second-half goals in his home debut with RSL (2-0-0, 6 points), which remained perfect on the season.
Alan Pulido picked up Sporting Kansas City's lone goal early in the first half. SKC (1-1-1, 4 points) conceded only two goals in its first two games before struggling to contain RSL's attack over the final 60 minutes.
SKC owned a two-match winning streak in the series between the two rivals coming into Saturday.
Kansas City struck first in the 17th minute. Pulido blasted home a right-footer from near the penalty spot after being left unmarked by RSL defenders.
Salt Lake leveled the score in the 35th minute. Andrew Brody sprung down the right side and fed the ball into Kreilach, who headed it home for the equalizer. Brody subbed in for Aaron Herrera in the 30th minute after Herrera exited with a quad injury then earned his first career MLS assist five minutes later.
RSL took its first lead in 52nd minute. Rubin settled a cross from Kreilach and threaded a ball from the edge of the 6-yard box through Pulskamp's legs, putting Salt Lake up 2-1.
Rubin added an insurance goal in the 77th minute. He tracked down a long ball, dribbled inside the box, and threaded a right-footed shot between three defenders to give Salt Lake a two-goal cushion.
RSL finished with a 10-6 advantage in total shots and a 4-1 advantage in shots on goal.