EUGENE, Ore. — Oklahoma and Oregon rode a roller coaster ride Six Flags would pay millions to patent Saturday.

But the 15th-ranked Sooners weren’t feeling any joy when they left Autzen Stadium. Not after coming up on the short end of a controversial 34-33 loss to 18th-ranked Ducks.

“We’re not supposed to lose that game; that’s the way the whole team feels and the coaches feel,” linebacker Rufus Alexander said.

He’s right.

Adrian Peterson rushed for 211 yards and Paul Thompson threw for another 174 and another score.

But it was overshadowed by the Sooners’ defensive meltdown in the final 72 seconds that allowed OU’s 13-point lead evaporate into a head-scratching loss.

Oregon quarterback Dennis Dixon and a controversial on-side kick recovery doomed the Sooners to their first loss of the season.

Dixon threw for 341 yards and ran for 34 more. The last of his two touchdown passes — a 23-yard toss to Brain Paysinger — gave the Ducks the win.

“I always think we have a chance,” Dixon said. “There’s no doubt in my mind that our offense can drive the ball down.”

The Sooner defense provided little debate to that notion. It allowed 501 yards and were hit for big play after big play.

“In the end, you have to be able to make some plays,” OU coach Bob Stoops said. “We have to be smarter finishing.”

Oregon had jumped out to an early lead, but Peterson’s 17-yard touchdown run on the first play of the fourth quarter put OU up 27-20. The Sooner workhorse ran it 34 times and gained 145 yards in the fourth quarter. It was his fifth career game with more than 200 yards.

And OU appeared to be pulling away at that point. The defense tightened and Garrett Hartley connected on field goals of 20 and 22 yards with the last one giving the Sooners a 33-20 lead with 3:12 left.

But that’s when OU’s fortunes changed in a very bad way and very quickly to boot.