CSU fell to 8-10 overall this year.
UCSB took a 2-0 lead in the top of the second, but Humitz answered with a two-run homer in the bottom of the second to knot the game at 2-2.
Joecken's solo homer in the third gave CSU a 3-2 lead, but UCSB responded with four runs in the fourth to take a 6-3 lead. Riley Ries had an RBI sacrifice fly in the sixth to slice the deficit to 6-4, but the Gauchos scored an insurance run in the sixth to regain a three-run lead.
The Vikings threatened with two runners on and just one out in the sixth and a Joecken two-out triple in the seventh, but could not push another run across.
CSU returns to action at the Bank of Hawaii Rainbow Wahine Classic from Wednesday through Saturday (March 14-17) with six games.