TUCSON, Ariz. (AP) -- Sean Mannion threw for a career-high 433 yards and hit Connor Hamlett on a 9-yard pass with 1:09 left for his third touchdown, lifting No. 18 Oregon State to wild 38-35 win over Arizona Saturday night.
Oregon State (3-0, 2-0 Pac-12) took a 17-0 lead, Arizona charged back and the teams traded scores in the second half of a game filled with big plays and 1,158 yards of combined offense.
Arizona (3-2, 0-2 Pac-12) took a 35-51 lead with 5:34 left when Matt Scott hit Austin Hill on a 7-yard touchdown. That left too much time for Mannion, who moved the Beavers 75 yards in 10 plays for the TD pass to Hamlett that gave coach Mike Riley his 75th win at Oregon State, breaking Lon Stiner's school record.
Storm Woods ran for 161 yards and a touchdown for the Beavers, off to their first 3-0 start since 2002.
Markus Wheaton caught 10 passes for 166 yards and a pair of touchdowns, and Brandin Cooks caught nine passes for 149 yards for the Beavers.
Arizona's Matt Scott threw for a career-high 403 yards and three touchdowns, but had two interceptions, including one near midfield in the final minute. Ka'Deem Carey ran for 115 yards and two touchdowns for Arizona, which has lost two straight after opening 3-0.
Oregon State had a strange, stop-and-start season before arriving in the desert.
The Beavers had their opener against postponed due to a hurricane, faced a ranked opponent the second week, followed by a bye and another ranked opponent.
They no trouble keeping a rhythm, knocking off No. 13 Wisconsin at home and No. 19 UCLA in the Rose Bowl behind a stingy defense and Mannion's arm.
Oregon State kept the same theme going early against Arizona.
Mannion was sharp early, hitting Cooks on a 57-yard pass in the first quarter to set up a 2-yard touchdown pass to Wheaton in the back of the end zone.
Next series, Mannion hit Wheaton for a 51-yard gain, leading to Romaine's 30-yard field goal.
Mannion found Kevin Cummings next, on a 38-yard pass to position Tyler Anderson for a 1-yard touchdown dive that put the Beavers up 17-0.
Oregon State's defense looked pretty good, too - at least for a while.
The Beavers bogged Arizona down in the first quarter and held when the Wildcats had their first sustained drive, which ended with John Bonano pushing a 30-yard field goal wide right after Scott was called for intentional grounding.
That wasn't a good sign for the Wildcats, who went 0-for-6 in the red zone in a 49-0 loss to Oregon last week.
Arizona managed to end its red-zone woes late in the second quarter, though, when the officials checked the replay to see if Carey fumbled at the 1-yard line and determined he actually went into the end zone for a score that cut Oregon State's lead to 17-7.
That drive seemed to be the spark the Wildcats needed.
Arizona kept rolling on its opening drive of the second half, quickly marching 91 yards in 10 plays for a 3-yard pass from Scott to Hill.
The Wildcats needed a minute to score again, this one a 24-yard run up the middle by Carey, who carried a couple of Oregon State defenders into the end zone with him to put Arizona up 21-17.
Scott made a mistake on the next drive, when Jordan Poyer missed an interception at midfield, then got it when the ball caromed off Richard Morrison. That set up a 1-yard touchdown run by Woods to give Oregon State the lead back.
Woods followed with a mistake of his own, losing a fumble at Oregon State's 40. Scott then threw to the corner of the end zone to Dan Buckner, who's over-the-shoulder, 16-yard TD catch put the Wildcats up 28-24.
Mannion's turn was next. Using a pump fake, he got the entire right side of Arizona's defense to bite and winged a 20-yard touchdown to Wheaton that put the Beavers back out front.
Scott answered, marching the Wildcats for a 7-yard touchdown pass to Hill, who dived in the final yard to make it 35-31.
He just left too much time for Mannion and the Beavers.