Loyola (21-9) will try to shake off the disappointment of not getting a berth in the NCAA tournament despite an RPI of 44 and victories over tournament teams Utah and St. Mary's. Junior guard Bryn Britton and senior guard Taryn Reynolds lead the Lions.
UNLV is 18-9 overall, 8-6 in the Mountain West Conference.
Loyola, 10-4 in the West Coast Conference, is 2-0 against teams from the Mountain West, beating San Diego State and Utah.
Pepperdine (20-10) plays Arizona at Tucson, Ariz., in another first-round game. The Waves have won 20 or more games for the fourth season in a row and earned their third consecutive postseason berth.