Castrillon scored his third goal of the season on a headeer in the 61st minute, and Rivero added his first MLS goal in the 74th. Brian Mullan assisted on both goals.
Colorado improved to 5-5-0, and Dallas dropped to 3-4-3.
Hernandez received a first yellow card in the 25th minute for dissent, then got another when he failed to pull out of a late challenge on Rivero in the 34th.
Perez drew a straight red card for reckless tackle on Drew Moor.