Arizona (17-16, 5-9 Pac-12) started the game hitting well. Austin Wells doubled to right-center and Nick Quintana doubled down the left field line to score Wells.
After, though, pitching for both teams took over.
Arizona starter Quinn Flannagan allowed just three hits in the first four innings.
But in the fifth, Cal third baseman Hace Smith doubled with one out. The next batter grounded a ball to shortstop Cameron Cannon, whose throw sailed right past Wells’ glove at first to allow Smith to score and tie the game at 1.
One inning later designated hitter Grant Holman hit a two-run home run off Flannagan to center to give the Golden Bears a 3-1 lead.
Nate Brown came in to relieve, and after he finished the sixth he allowed the first two runners to reach in the seventh. Coach Jay Johnson decided to replace Brown with sophomore Gil Luna, who gave up a two-run single to the second batter he faced to give Cal a commanding 5-1 lead.
Cal starter Jared Horn was fantastic. After allowing the first-inning run and a second-inning hit, he did not allow another baserunner until the eighth and finished with nine strikeouts and zero walks in eight innings.
“He pitched a better game than anyone has pitched against us all year,” Johnson said. “I’m going to really tonight give the credit to the pitcher.”
Wells’ first-inning double extended his on-base streak to 27 games, while outfielder Donta Williams had a 23-game on base streak end on Saturday.
Arizona will try to avoid being swept at home at 1 p.m. Sunday at Hi Corbett Field.