Mora, a freshman at UCLA, scored from a Maria de Jesus Castillo feed to pull the Mexicans even in the 65th minute. Dominguez, the W-League scoring champion and MVP with the Kansas City Mystics over the summer, tallied 44 seconds later from a Mora pass.
Marcia Rewolt's 25-yard blast off the underside of the crossbar gave Long Beach State a 47th-minute lead.
Mexico, which plays at UCLA on Sunday, is preparing for the Oct. 28-Nov. 9 CONCACAF Women's Gold Cup, the region's qualifier for next year's World Cup.