Cal star guard Justin Cobbs scored all 20 of his points after halftime and led five Cal players in double figures.
Roberto Nelson led Oregon State (9-7, 1-3) with 26 points and nine assists, while Angus Brandt added 22 points and Eric Moreland chipped in 14 points and 11 rebounds.
Those kinds of offensive numbers should spell victory for Oregon State every day of the week.
Oregon State in the first half shot 63 percent from the field and 7-for-8 from beyond the arc to lead 45-35 at intermission, but the Golden Bears needed only six minutes in the second half to take a one-point lead.
Oregon State was held to 10 field goals in the second half and fell to 5-72 over their last 77 games when trailing with five minutes left to play.
But as bad as the issues were on the offensive end in the second half, they paled in comparison to the ones on defense. The Beavs played an ambivalent style of defense on Saturday and in this conference, that's a prescription for a defeat.