Mike Reuvekamp made his only hit count.
Reuvekamp, who was 1 for 7 at the plate, drove in the game-winning run with a single in the bottom of the 12th to give host Cal a 7-6 win over Arizona on Saturday.
UA led 6-5 before Cal scored in the ninth to send the game into extra innings.
Zach Gibbons had two hits and two RBIs for the Wildcats (20-31, 9-20 Pac-12).
His two-run single in the seventh tied the game at 5.
The teams play the rubber game of the series at 3 p.m. today on Pac-12 Arizona.