It ended OSU's 12-game Pac-12 losing streak and including several rushing marks that landed into Oregon State's record book.
But second-year coach Gary Andersen wanted the Beavers (2-3, 1-1) to keep Saturday night's 47-44 win over California in perspective.
''It's a win in the Pac-12, obviously,'' Anderson said. ''It hasn't happened in a long time. So it should give them an understanding of what it takes to win a game in the Pac-12.
''I don't know if it's a program-defining moment. I wouldn't necessarily say that. I expect those to be down the road.''
Garretson's game-winner was practically a walk to the end zone during the final 10 yards, but the outset of the play was hair-raising. Garretson bobbled the center snap, but quickly recovered, cut to his right and sprinted to the end zone to put away California (3-3, 1-2).
''Thank God I had that left glove on. These guys are giving me (a hard time) about it because it's a lineman's glove, but it is what it is, and it stuck, so we're good,'' Garretson said.
It was fitting that Oregon State won the game on a running play, because the Beavers ran over California most of the night.
Ryan Nall ran for 221 yards and three touchdowns but left the game early in the fourth quarter with a leg injury. Garretson rushed for 105 yards and two touchdowns and completed 13 of 24 passes for 85 yards.
Oregon State ran for 474 yards, a school record against a Pac-12 opponent. The Beavers had a season-high 559 yards, though it almost wasn't enough, as they blew a 17-point, fourth-quarter lead.
Davis Webb threw for 113 yards, well under his season average of 428.6 passing yards, for California (3-3, 1-2). Khalfani Muhammad ran for 165 yards and a touchdown while Tre Watson had 134 yards and two touchdowns.
But the poor run defense and lack of offense for much of the game - 180 yards through three quarters - left Cal coach Sonny Dykes perplexed.
''Our guys fought hard in the second half, but it was too little, too late,'' Dykes said. ''I told them guys, I didn't think we deserved to win. We sleepwalked through the first half, for sure.''
Nall ripped off runs of 80 and 62 yards during the third quarter as Oregon State increased its lead to 34-17. Artavis Pierce scored on a 2-yard run that made it 41-24 with 10:35 left when it began to unravel.
California trimmed the deficit to 41-38 with 2:41 left and Matt Anderson's 29-yard field goal with five seconds remaining sent the game into overtime.
OSU's defense forced a three-and-out by California in overtime, and Anderson kicked a 39-yard field goal to set the stage for Garretson's game-winner.
''The defense studded up and made them kick a field goal. We made the play we needed to make to win the game,'' Andersen said.
CALIFORNIA: The Bears lost their seventh consecutive road game, and it won't look pretty on video next week. The Pac-12's worst rushing defense continued to struggle, giving up an average run of 10.1 yards to Oregon State.
OREGON STATE: The Beavers rank No. 100 or lower in rushing, passing and total offense nationally, but didn't look the part in the first half when they scored on their first three drives. Led by the bruising runs of Nall, Oregon State also scored on its first four drives of the second half.
NALL APPEARS OK
Nall said he reinjured his foot early in the fourth quarter, an injury he's been dealing with this season. Andersen said he expects Nall, whose 221 yards was a career high and 10th best in Oregon State history, will be ready to play next Saturday against Utah.
When Nall left in the game with 11 minutes remaining, he was within 18 yards of the Reser Stadium record of 239 rushing yards, set by Steven Jackson.