EUGENE, Ore. (AP) -- Marcus Mariota wore a T-shirt emblazoned with the word ''Success.'' It was a fitting wardrobe choice after this victory.
Mariota accounted for four touchdowns in the first half of No. 3 Oregon's season-opening 62-13 win against South Dakota on Saturday night.
Mariota threw for 267 yards and three touchdowns, and then ran for one more before sitting out the final two quarters.
His 62-yard pass to Dwayne Stanford on Oregon's first series of the game gave him the Ducks' career record for touchdowns with 79 (64 pass, 14 rush and one reception), surpassing Joey Harrington.
''Marcus did what Marcus does,'' said running back Byron Marshall, who was Oregon's top receiver with eight catches for 138 yards and two touchdowns.
Freshman Royce Freeman, a five-star recruit out of Imperial, California, ran for 75 yards and two more scores for the Ducks, who won their 10th straight home opener.
Trevor Bouma ran for a 3-yard TD and Miles Bergner kicked a pair of field goals for the Missouri Valley's Coyotes, who went 4-8 last season. Kevin Earl completed 13 of 26 passes for 136 yards, but left in the third quarter with what coach Joe Glenn said was likely a fractured thumb.
Mariota, who opted to return to Oregon after flirting with an early departure for the NFL, threw for 3,665 yards and 31 touchdowns last season with just four interceptions. Considered among the top dual-threat quarterbacks in the country, he also rushed for 715 yards and nine scores.
With his third touchdown pass on Saturday night, he tied Darron Thomas for career passing touchdowns at Oregon with 66. He completed 14 of 20 passes.
''We scored on our first three possessions, which is always good,'' Mariota said. ''We've had our moments, including last year, when we've started out slow. For us to come out and start fast and do what we were able to do, it sets a good foundation for the rest of the season.''
The Ducks finished 11-2 last season, capped by a victory over Texas in the Alamo Bowl. Oregon's two late-season losses, to Stanford and Arizona, came after Mariota injured his left knee, effectively taking the Ducks out of the Pac-12 championship race and a bid for a national title.
Following Mariota's opening TD strike to Stanford, South Dakota drove into Oregon territory on its opening series and scored on Bergner's 47-yard field goal.
Mariota hit Marshall with a 41-yard touchdown pass and Freeman scored on a 1-yard dive to give Oregon a 21-3 lead.
South Dakota then drove as close as the Oregon 3 but settled for Bergner's 25-yard field goal.
Midway through the second quarter, Marshall's 54-yard dash for the end zone ended with a fumble on the 1-yard line for a touchback. But the Coyotes fumbled after getting the ball, and Mariota hit Marshall with an 11-yard touchdown pass.
''Huge mental mistake,'' Marshall said about the touchback. ''I've never made a dumber play in my life. ... It happens, no one's perfect. But a mistake like that could be costly in a different game and I've got to be better than that.''
Bouma, who led the Coyotes with 781 yards rushing as a redshirt freshman last season, ran for a 3-yard touchdown with 1:36 left in the first half. Mariota answered with 1-yard keeper to make it 41-13 lead at the break.
''They're really special with Mariota at the wheel. He's who I thought he was,'' Glenn said. ''He's special and time will bear that out.''
Oregon senior cornerback Ifo Ekpre-Olomu, who like Mariota decided to return for a final season at Oregon, left in the first half with what appeared to be a non-contact injury to his left foot or ankle.
Afterward, Ekpre-Olomu said he had been battling an ankle injury and left the game as a precaution.
Oregon rested many of its starters in the second half. Freshman Charles Nelson scored on a 50-yard punt return to give the Ducks a 48-13 lead in the third quarter.
The game gave Oregon some things to work on before hosting No. 8 Michigan State next weekend. The defending Big Ten champions routed Jacksonville State 45-7 on Friday night.