Cali Denson hit one of two free throws with 1.8 seconds to go to beat the Thunder at the Nike Interstate Shootout in Lake Oswego.
Mountain View (3-7) had a five-point lead with two minutes to go. But Denson hit a 3-pointer to help Milwaukie take the lead.
Lauren Coop hit a free throw to tie the game at 49-49 with 45 seconds to play.
Coop had 14 to pace the Thunder (3-7). Dejah Wilson added 12 and Paytin Ballard had 10.
Mountain View faces David Douglas of Portland at 12:30 p.m. Friday.
MILWAUKIE 50, MOUNTAIN VIEW 49
MOUNTAIN VIEW (3-7) — Jocelyn Sampson 0, Dejah Wilson 12, Paytin Ballard 10, McKenna Stephens 0, Arielle Pinzone 2, Lauren DeLargy 6, Lauren Coop 14, Gillian Murphy 0, Jenna Carlson 5. Totals 18 (2) 11-14 49.