EUGENE, Ore. (AP) - Byron Marshall ran for 133 yards and three touchdowns and No. 2 Oregon wore down No. 12 UCLA's stout defense for a 42-14 victory on Saturday night.

Marcus Mariota threw for 230 yards and a score and De'Anthony Thomas returned from a three game absence to run in another for the Ducks (8-0, 5-0 Pac-12).

The Bruins (5-2, 2-2) went into halftime with the score knotted at 14 but were shutout by the Ducks in the second half.

Brett Hundley completed 13 of 19 passes for 64 yards and a touchdown but also threw two interceptions, including one early in the fourth quarter that led to an Oregon touchdown. He also ran for 64 yards and a score.

UCLA has not won at Autzen Stadium since 2004, and hasn't defeated the Ducks since a 16-0 blanking in 2007. The two teams last met in 2011, when Oregon downed UCLA 49-31 in the inaugural Pac-12 championship game.

The Ducks are the highest ranked opponent the Bruins have faced since they played the No. 1-ranked Ducks in the 2010 season. Last weekend UCLA fell 24-10 to No, 13 Stanford.

Oregon, ranked No. 3 in the initial BCS rankings released last weekend, was coming off a 62-38 victory at home over Washington State. The Ducks have played one other game against a ranked opponent this season -a 45-24 victory over then-No. 16 Washington at Husky Stadium

Oregon got off to a poor start, stymied by its own mistakes and UCLA's defense. On the Ducks' second play from scrimmage, Keanon Lowe fumbled a pass from Mariota. The turnover led to Hundley's 4-yard touchdown run to give the Bruins the early lead.

But Rodney Hardrick ran 66 yards on a fake punt and Thomas finished it off with a 1-yard dive for an Oregon touchdown to even the score.

Thomas had missed the last three games after injuring his right ankle on the opening kickoff in Oregon's 55-16 victory over California on Sept. 28, slipping on turf slick from a driving rain.

Thomas was the Ducks' leading rusher with 338 yards and six touchdowns in three games before he was injured.

Oregon went ahead 14-7 early in the second quarter with a 40-yard scoring run from Marshall, a sophomore who took over as starter in Thomas' absence.

But Alejandro Maldonado's punt for the Ducks was blocked late in the half, putting UCLA in Oregon territory. The Bruins capitalized on Hundley's 11-yard scoring pass to Thomas Duarte to even the game at 14.

Midway through the third quarter, Mariota fumbled on first-and-goal at the UCLA 5, but the Bruins were forced to punt and the Ducks quickly responded with Marshall's 11-yard touchdown run.

Avery Patterson intercepted Hundley early in the fourth quarter and the Ducks went on to score on Mariota's 8-yard pass to Bralon Addison. Marshall added a 3-yard touchdown dash with 8:47 left and freshman Thomas Tyner ran for a 2-yard TD with 2:25 to go for the final margin.

It was Marshall's fifth straight game with at least 100 yards rushing this season.

The Bruins were without junior tailback Jordon James, who missed his third straight game with an ankle injury. He had run for more than 100 yards in each of the Bruins' first three games.

The Bruins were also dealing with injuries on their offensive line, and as a result the team started three true freshman: Alex Redmond at right guard, Caleb Benenoch at right tackle and Scott Quessenberry at left guard. The Bruins have played 17 true freshmen this season.