Tyler Copp scored 10 of his game-high 20 points in the fourth quarter and the Titans stayed alive in the 4A bi-district tournament.
Copp made some clutch 3-point shots, plus key baskets by Kyle Mercer and Trent Cowan kept Union in front.
The Titans (16-7) face another loser-out game at 6:15 p.m. Saturday at Curtis High School, against Stadium.
UNION 57, OLYMPIA 48
OLYMPIA — Johnson 14, Champlin 10, Leonard 8, Fortier 8, Naipo 5, Setting 2, Falorer 1. Totals 18 (4) 8-14 48.
UNION (16-7) — Tyler Copp 20, Trent Cowan 9, Seaver Whalen 6, Kyle Mercer 4, Jeff Wu 5, Micah Paulson 13, Skillful Davis 0, Isaiah Robinson 0, Derek Derryberry 0, Riley Hawken 0, Spencer Martin 0. Totals 19 (8) 11-14 57.