Rivero found the back of the net in each half, but a duo of Azusa Pacific players each scored twice in a 4-2 win in Pacific West Conference play.
Dixie State dropped its fourth consecutive league match to fall to 4-7-2 within the PacWest and 5-10-2 overall.
Oktay Balut and Luke Ackermann had two goals each for the Cougars (11-5-1, 9-4 PWC).
Rivero gave the Red Storm the lead in the 17th minute. He picked up a loose ball after the APU defense failed to clear it out of the zone for the goal. Later, Rivero struck again at the 80:00 mark deflected off the keeper set up off a Tyler Albretsen pass.
Azusa Pacific won the shot battle 19-6.
Tyler Walters made six saves in goal for Dixie State.
The regular season concludes next Saturday with a return match with the Cougars. Senior Day festivities at Hansen Stadium begin at 5 p.m