The Ducks lost none of their quick-strike scoring ability without their injured quarterback and running back. Thomas was out with a knee injury and James missed his second straight game while recovering from a dislocated elbow.
Barner reeled off touchdown runs of 4 and 84 yards and Bennett found running back De'Anthony Thomas for a 14-yard touchdown and tight end David Paulson from 31 yards out.
Barner gained 115 yards on 10 carries before giving way to a bevy of other backups and Bennett added 69 yards on the ground to go with 156 yards through the air on 11 of 20 passing. He, too, was a sideline spectator before the third quarter was over.
Both Barner and Bennett averaged 11.5 yards a carry, but De'Anthony Thomas did them one better, averaging 12.5 yards on his four rushes.
The Folsom Field crowd figured the Ducks were piling on the Buffaloes (1-6, 0-4) right away when punter Jackson Rice took the direct snap after their first touchdown and plowed into the end zone for a 2-point conversion and an 8-0 lead.
The Ducks' defense got into the act when linebacker Michael Clay intercepted Tyler Hansen's pass at the Buffs 32 and raced into the end zone in the second quarter. Alejandro Maldonado's extra point was wide right, leaving the Ducks ahead 35-0 at halftime.
Hansen, who boasted during the week that he was "100 percent healthy" with all his teammates going down around him, sustained a concussion on a slide that didn't draw a flag late in the first half and was replaced by freshman Nick Hirschman the rest of the afternoon.
The Buffaloes started the game without more than a dozen injured players, most notably running back Rodney Stewart and wide receiver Paul Richardson, who accounted for nearly 60 percent of Colorado's yards from scrimmage before Saturday. Both are out with knee injuries.
They were also missing their biggest playmakers on defense in linebacker Douglas Rippy, their leading tackler who underwent surgery during the week for a torn ACL, and strong safety Ray Polk, who is the poster player of the banged-up Buffaloes with a sprained wrist, a cracked sternum and a concussion.
With so many key players sidelined, the Buffs were hoping something else might slow down the Ducks — altitude. Boulder is nearly 5,000 feet higher than Eugene, Ore., making a no-huddle offense a little more lung searing for the speedy Ducks, who came in with half of their 38 TD drives eating up 1:39 or less.
Indeed, Oregon's offense failed to score on either of its two second-quarter possessions before a kneel-down on the final play before halftime.
After Maldonado added a 36-yard field goal, the Buffaloes finally got on the scoreboard when Terrel Smith corralled Harris in the end zone for a safety with 1:32 left in the third quarter.
This marked the first time the Buffs' offense failed to score in a home game since a 31-7 loss to Texas in 2004.