Fresno State turned to sophomore right-hander Garrett Mundell to end a string of disappointing outings for the pitching staff.
It worked well for three innings, as Mundell escaped a bases-loaded jam in the first unharmed, then faced the minimum over the next two innings.
But with two out in the fourth, Cal's Michael Theofanopoulos made his first hit this season count, mashing a two-run homer that set up the Bears' 8-1 win.
Fresno State got to within 2-1 with an unearned run in the top of the fifth on Taylor Ward's sacrifice fly but that was it.
Cal freshman right-hander Ryan Mason allowed only that in his five innings, striking out seven, and three relievers finished up the four-hitter.
The Bears are 5-0 at home while evening their season record at 7-7. Fresno State (3-10) has lost the first two in the series, three straight overall and its first six this year on the road.
Chris Paul made it 8-1 with a three-run home run off Tyler Stirewalt in the seventh. It was Paul's first of the season for the Bears.
The teams play at 1 p.m. today in Berkeley.
Softball: 'Dogs lose out to rain; Arbino fans 15
The Bulldogs made it to just the second inning of their Fresno State Classic game against Oregon before rain forced its cancellation and also postponed a planned second game against Oregon State.
Fresno State was a 7-6 winner with a last at-bat rally against Iowa State in the opener Thursday at Bulldog Diamond.
San Diego State beat Iowa State 7-4 as former Clovis High star Rebecca Arbino struck out 15 while pitching a nine-inning four-hitter, with one run earned.
Arbino had a no-hitter through 61/3 innings, but after the Cyclones scored two in the eighth, it took Aztecs sophomore Kayla Jordan's walk-off grand slam in the ninth to win it.
Ninth-ranked Oregon beat San Diego State 3-2 with a run in the seventh. No. 23 Oregon State, coached by four-time Bulldogs All-American Laura Berg, beat Saint Mary's 7-3.
Men's golf: Bulldog sits atop leaderboard
Fresno State's Troix Tonkham shot a 70 to share the first-round lead at the Bandon Dunes Championship in Bandon, Ore.
The Bulldogs (301) are in ninth, trailing leader Oregon by 10 strokes.
Lacrosse: Second-half rally falls far short
Anjelica Fuccillo's hat trick was not enough to save Fresno State from a 17-10 loss to Winthrop in a lacrosse match in storm-threatened Denver.
Natalie Harrington and Margaret Wolford had two goals each for Fresno State (1-2). Shannon Gallagher's six led Winthrop (4-3).
The Bulldogs' game with host Denver has been moved to 11 a.m. Sunday.