Sabario broke a scoreless tie in the 20th minute when he right-footed a shot from the box that ended up in the top right corner of the net off an assist from Tony Beltran.
Espindola doubled the lead for first-place RSL (5-1-0) in the 57th minute on a controversial score. Espindola poked home the ball after Rapids goalie Matt Pickens signaled the Salt Lake forward had touched it with his hand.
Replays seemed to confirm a hand ball, but the goal stood and Pickens was handed a yellow card after arguing vociferously.
Colorado (3-2-0) fell to 0-5-2 in its last seven games in Utah.