The Titans will play for the Tournament of Champions title today in Seattle after beating Foss in the semifinals.
Tyler Copp scored a team-high 18 points and hit a 3-pointer late in the game to give Union a seven-point cushion.
Kyle Mercer was 7 for 8 from the free-throw line down the stretch, and Micah Paulson had 12 points for Union. Seaver Whalen added seven rebounds, six assists to go with three points.
The Titans will face host Franklin of Seattle at 8 p.m. today for the tournament title.