BOULDER, Colo. -- Marcus Mariota turned Oregon's shaky start into an afterthought.
Mariota threw for five touchdowns and ran for two scores, and second-ranked Oregon shrugged off an early deficit to roll to its 17th consecutive road victory by beating Colorado 57-16 on Saturday at Folsom Field.
"Marcus was huge," said wide receiver Josh Huff, who caught two touchdown passes. "Any time he gets comfortable and gets into a rhythm, it's tough to stop this offense. We've just got to learn how to start off faster. If we start off faster, there's no one that can stop us but ourselves."
Bralon Addison also had two touchdown receptions and cornerback Terrance Mitchell had two interceptions leading to two scores for Oregon (5-0, 2-0 Pac-12). Byron Marshall added 120 yards rushing on 23 carries.
The Ducks, also the country's second-ranked team in scoring, surpassed 50 points in their fifth straight game to open the season, a first for the school.
"We started off a little slow, but we started to get things rolling and I'm proud of the guys for fighting through that adversity," Mariota said. "It's always going to make us a little better."
Mariota completed 16 of 27 passes for 355 yards in just under three quarters before being relieved by understudies Jeff Lockie and Jake Rodrigues. Mariota also rushed for 43 yards, including scoring runs of 1 and 2 yards.
Connor Wood completed 11 of 33 for 205 yards for Colorado (2-2, 0-2 Pac 12). Paul Richardson had five receptions for 135 yards and also threw a 75-yard touchdown pass to fellow receiver D.D. Goodson on a flea-flicker.
"We came out hard. We fought hard," Colorado cornerback Greg Henderson said. "We just have to learn from everything we did wrong and everything we did right. We still have a long season ahead."
Building on a 27-point lead at the break, Mariota connected with Addison on a 44-yard touchdown pass early in the third quarter after the two teamed up on a 75-yard strike earlier.
Later, he went back to Huff for his second touchdown catch, a 26-yarder giving the Ducks a 57-16 lead with 6:50 remaining in the third quarter. At that point, Oregon coach Mark Helfrich called it a day for his starting quarterback.
Trailing by two points midway through the first quarter, Oregon outscored the Buffaloes 35-6 in a 17-minute stretch to take a 43-16 halftime lead.
"Obviously, we didn't get off to a great start in any phase and that's on me," Helfrich said. "But I like the way we rallied."
Colorado's Will Oliver kicked his second and third field goals of the day, covering 22 and 31 yards, at the start of the second quarter but that just stalled Oregon's juggernaut for the moment.
The Ducks cranked up their offense once again, with Mariota finishing one long drive with his second short touchdown run, and completing another with his third touchdown pass, a 4-yarder to Huff.
"They're really fast, really hard to get aligned to and if you don't line up, they'll capitalize on those mistakes," Colorado linebacker Addison Gillam said.
Colorado proved to be a pesky opponent initially. The Buffaloes took a 10-8 lead on a fake end-around, when receiver Richardson took a handoff from Wood, pulled up and threw downfield to Goodson for a 75-yard score.
Oregon snuffed any visions of an upset with a three-touchdown blitz in the last five minutes of the first quarter, including two set up by interceptions of Wood by Mitchell.
Thomas Tyner's 2-yard touchdown run after Mitchell's first interception put Oregon back in front 15-10, and after a Colorado punt, Addison got behind Colorado's secondary to catch a 75-yard strike from Mariota.
Mitchell stepped in front of Richardson for his second interception, and three plays later, Mariota passed 17 yards to Keanon Lowe to put Oregon up 29-10.
NOTES: Mariota stretched his streak to seven games in which he has thrown for at least one touchdown pass and run for another. ... Tyner, a freshman, has run for a touchdown in each of the four games he has played. ... Colorado honored its winningest coach, Bill McCartney, during halftime ceremonies. He's being inducted into the College Football Hall of Fame in December. McCartney was 93-55-5 as Colorado's coach from 1982 to 1994, including guiding the Buffaloes to their only national championship in 1990. ... With his first catch, Richardson became the 12th Colorado player with at least 100 career receptions. He has caught a touchdown pass in four consecutive games, one shy of the school record. ... Oregon improved to 3-0 against Colorado as a Pac-12 opponent, outscoring the Buffaloes 172-32.