EUGENE, Ore. — Sometimes the sequels are better.

In Bob Chesney’s return to Autzen Stadium after Oregon knocked his James Madison squad out of last season’sCollege Football Playoff, his No. 21 Bruins met the moment and toppled the No. 13 Oregon Ducks 17-15 Saturday.

The victory ended UCLA’s five-game losing streak against Oregon and was the Bruins’ first triumph in Eugene since 2004. Chesney became the first UCLA coach to start his tenure 5-0.

He took a moment to soak it in before finding Oregon coach Dan Lanning for the postgame handshake.

“I was here before,” Chesney said. “They ended our season and sent us home. And I think (I) just wanted to take a second and just feel it and see it one more time before I walked up to him.”

Chesney said earlier in the week that UCLA needed a “near-perfect” game to beat the Ducks. He was wrong. In a defining game that many thought would expose problems masked by UCLA’s early-season success, the Bruins — though imperfect — vociferously announced their arrival to the college football world as legitimate playoff contenders.

And while the Bruins proved some doubters wrong, they didn’t really care to.

“We don’t focus on outside chatter,” senior linebacker Sammy Omosigho said. “That has no meaning to us, no focus to us, no value to us. We focus on ourselves and the jersey we have on right now.”

Oregon turned the ball over seven times. With quarterback Dante Moore still recovering from a head injury he sustained against USC, Ducks backup Dylan Raiola completed six of 19 passes for 43 yards and two interceptions before he was replaced by third-string quarterback Brock Thomas, who went 11-of-15 passing for 156 yards, one touchdown and no turnovers.

UCLA quarterback Nico Iamaleava, who left the game late in the second quarter after sustaining an injury to his right leg, completed 10 of 17 passes for 162 passing yards and two interceptions. Backup quarterback Ty Dieffenbach completed three of six passes for 43 yards, one touchdown and no turnovers.

UCLA quarterback Ty Dieffenbach, left, and wide receiver Shane Rosenthal celebrate.

UCLA quarterback Ty Dieffenbach, left, and wide receiver Shane Rosenthal celebrate after the Bruins’ win over Oregon.

(Tom Hauck / Getty Images)

Wayne Knight remained the key to UCLA’s offense, finishing with 103 yards and a touchdown in 22 carries and three catches for 12 yards and another touchdown.

“I just know the guys up front are going to do a great job,” Knight said. “I trust them wholeheartedly.”

Although the halftime score wasn’t lopsided, UCLA dominated through two quarters. The Bruins earned 241 yards against Oregon’s 58. UCLA held a 162-36 advantage in passing yards and a 79-22 edge in rushing yards.

On third downs, the Ducks were far from the 50% conversion rate they held entering the contest, going 0 for 7 in the first half. Though UCLA wasn’t much better, sitting at one for eight, its 10 first downs against Oregon’s three meant the Bruins possessed the ball 10 minutes more than the Ducks.

However, UCLA only led 10-6 at halftime. The Bruins failed to take care of the ball. Specifically, Iamaleava struggled, fumbling once and throwing interceptions to Oregon’s Koi Perich and Jerry Mixon.

His fumble in the first quarter on UCLA’s one-yard line immediately led to a Jordon Davison touchdown, and his two interceptions in the final two minutes of the half were egregious, his second occurring while the Bruins were in field-goal range.

Although not directing his ire at Iamaleava, Chesney wasn’t happy with how the first half unfolded.

“Disappointed with the first half to be honest with you,” Chesney said. “Just really disappointed with how many opportunities we left out there. … We can’t put ourselves in those situations that we did, and I think that got this game really close at halftime.”

Unfortunately for Iamaleava, a chance at some redemption in the second half did not materialize because of his injury. He stayed in the locker room for most of the third quarter, returning to the sideline in street clothes.

UCLA quarterback Nico Iamaleava looks to pass against Oregon on Saturday.

UCLA quarterback Nico Iamaleava looks to pass against Oregon on Saturday.

(Lydia Ely / Associated Press)

“Nico was close to being able to come back today,” Chesney said. “I thought he got hit in the thigh, but there might be a little more to it. We’ll have to figure that out as we go through the process tonight and tomorrow.”

Thankfully, Dieffenbach was ready.

“They went with me, so when I heard that, it was tunnel vision, just ready to go execute,” Dieffenbach said. “[Chesney] says the lights are gonna shine and somebody’s going to be exposed [or] you’re going to be revealed. That was kind of just the mentality today.”

A scoreless third quarter ensued. Not entirely uneventful, however, as UCLA forced another fumble and picked off Raiola again, ultimately leading Lanning to go with Thomas to begin the fourth quarter.

Starting the fourth with beautiful field position, the Bruins needed three plays to score. Dieffenbach found Knight for a nine-yard score, giving UCLA a 17-6 lead with just over 13 minutes left.

On Oregon’s next possession, facing a fourth-and-one, UCLA stuffed Thomas, once again punching out a fumble. A little over 11 minutes remained as a noticeable number of Oregon fans began heading toward the exits.

But the Ducks showed some life. During a drive bolstered by a 36-yard pass from Thomas to Dakorien Moore, Oregon’s Gage Hurych hit a 26-yard a field goal with 5:16 left, cutting the lead to a possession.

The tide turned. Opening the next possession on its 43-yard line, Oregon needed just four plays to find the end zone, with Thomas tossing a 44-yard touchdown pass to Evan Stewart. A failed two-point conversion followed, but a UCLA face-mask penalty gave Oregon one more chance to tie the score.

The Ducks failed, with Tyson Ford and Jalen Woods stuffing Davison on the one-yard line.

UCLA eventually punted with 48 seconds remaining, pinning Oregon on its own 10-yard line. The Bruins’ defense withstood the Ducks’ final push and celebrated a signature victory during a turnaround season.

At 5-0, the Bruins will celebrate tonight. But Chesney plans to bring them back down to earth soon enough.

“Tomorrow, it’s going to be the same message: It doesn’t matter,” Chesney said. “Now we have to get better. How do we get better? We go back and look at the things we need to fix. We evaluate our personnel and see where we stand once we figure out whether some of these guys are coming back next week. There’s a lot of football left to be played, so it doesn’t matter. Getting better is always the message when we turn the corner, but not just yet. We’ll get to that tomorrow.”

UCLA players celebrate after defeating Oregon on Saturday.

UCLA players celebrate after defeating Oregon on Saturday.

(Tom Hauck / Getty Images)