SEATTLE -- Second-ranked Oregon passed its first serious test.
The Ducks were in a close game during the fourth quarter for the first time all season before turning back No. 16 Washington, 45-24, on Saturday in Pac-12 game at Husky Stadium.
It was Oregon's 10th straight victory over its rival to the north.
"It feels great," Oregon senior defensive lineman Taylor Hart said. "It was an exciting game. I can say I never lost to Washington in my career. That was a lot of fun today."
Oregon's lead was down to 31-24 in the fourth quarter before quarterback Marcus Mariota ran for a touchdown and threw a scoring pass to help the Ducks put away from the Huskies and improve to 6-0 overall, 3-0 in the conference.
After winning its first five games by an average of 48 points, Oregon had a tougher time against its first ranked opponent of the season.
"We responded really well," Oregon coach Mark Helfrich said. "The resolve of our team is special. The people that we have on this team are special. If we are up by some number or down by some number, it doesn't matter."
Mariota completed 24-for-31 passes for 366 yards and three touchdowns, while running for 88 yards and a touchdown to strengthen his Heisman Trophy chances.
"He's at the top of the Heisman list for a reason," Oregon senior receiver Josh Huff said. "He was excellent."
Byron Marshall ran for 106 yards and two touchdowns for the Ducks, while Bralon Addison had 157 receiving yards and two touchdowns. Oregon had 631 yards of total offense.
"Oregon is a good team and they have good players," Washington linebacker Princeton Fuimaono said. "They just made some plays and there were some plays we didn't make. We just didn't execute."
Oregon took the lead on a one-yard touchdown run by Marshall in the first quarter. The Huskies answered on third-and-goal when Keith Price found Austin Seferian-Jenkins for an eight-yard touchdown pass that tied the game, 7-7.
The Ducks scored on back-to-back drives in the second quarter to take a 21-7 lead at halftime.
Mariota threw a four-yard touchdown pass to Addison with 8:41 remaining in the second quarter. Marshall got his second scoring run, a 15-yarder, to push the Ducks ahead by 14.
Oregon is known for its quick-strike offense, but the Ducks moved slower than usual in the first half. Thirty-one of Oregon's 39 touchdown drives in its first five games lasted two minutes or less, but all three scoring drives in the first half Saturday lasted more than two minutes.
On fourth-and-one from the Washington 40-yard line, Bishop Sankey ran left and went almost untouched into the end zone for a 60-yard touchdown that got the Huskies within 21-14 barely over a minute into the second half.
Oregon needed only three plays before Mariota threw a 65-yard touchdown pass to Huff to push Oregon's lead to 28-14. Huff left the game in the second quarter because of a leg injury, but he returned after halftime.
Washington drove to Oregon's five-yard line on its next drive, but had to settle for a 30-yard field goal by Travis Coons to get within 28-17.
Oregon answered with a field goal by Alejandro Maldonado from 34 yards to go ahead, 31-17, with 3:16 left in the third quarter.
Washington got its second touchdown run from Sankey, a 25-yarder, right before the end of the third quarter to cut the Ducks' lead to 31-24.
Once again, Oregon had a response as the Ducks drove 66 yards in five plays. Mariota scored on a five-yard run to put the Ducks ahead, 38-24, with 13:55 left.
Mariota added a three-yard touchdown pass to Addison in the middle of the fourth.
"Oregon's ranking is deservedly so," Washington coach Steve Sarkisian said. "I thought our kids played hard, we fought and we showed a lot of resolve during the third quarter and battling back.
"We just unfortunately had a hard time containing Marcus Mariota."
Price passed for 182 yards and a touchdown, while Sankey ran for 167 yards and two touchdowns in addition to catching a team-high five passes for 38 yards.
The Huskies had 376 yards of total offense.
NOTES: Oregon played its second straight game without running back De'Anthony Thomas, who has an ankle injury. Thomas, who has 338 rushing yards and six touchdowns in three games this season, warmed up, but he stood on the sideline the entire game. ... Marcus Mariota has thrown a touchdown pass in all 19 games of his career, which ranks as the third-longest streak in the nation, five behind Fresno State's Derek Carr. ... Washington allowed seven points in the first quarter during its first five games and Oregon matched that with seven in the opening quarter. ... Oregon is 16-6 against teams ranked in the Associated Press Top 25 since Mark Helfrich, now the coach, arrived as offensive coordinator in 2009.