Little about the first month of his first season at USC had gone as Eric Musselman hoped. His USC offense struggled to score. His defense struggled to get stops. And on the glass, only a few of the 355 teams in Division I college basketball had been worse than the Trojans, who struggled to dispatch the likes of Grambling and Texas Arlington.

The shortcomings of a rapidly constructed roster had become evident to USC’s coach during that eight-game stretch. But after stumbling its way through the first month of the Muss era, here was a chance, in its Big Ten debut, for USC to stem the tide of those early-season struggles.

The Trojans seemed well on their way to seizing that opportunity Wednesday against Oregon, which sat atop the conference after a spotless 8-0 start. Then, in the final minutes, everything unraveled for USC in a 68-60 loss to the No. 12 Ducks.

A defense that, for most of the game, appeared transformed crumbled during the final 10 minutes, as Oregon got to the line again and again — 16 times in that stretch. Oregon guard T.J. Bamba, whom USC silenced for most of the game, hit a three-pointer with eight minutes remaining, and in an instant, the switch flipped.

“We can lead for 30 minutes,” Musselman said, “but it’s the last 10 minutes of play where we’re not used to winning as a unit.”

USC (5-4) still was clinging to a three-point lead with less than five minutes left when Trojans forward Saint Thomas lost the ball. Oregon needed just three seconds to hit a three, tying the score.

The next two possessions sealed the Trojans’ fate. With USC down three of its usual contributors, Musselman hoped to give little-used wing Kevin Patton Jr. some time down the stretch. But in the game’s most critical moment, the sophomore threw a bad pass that was picked off, resulting in another Oregon three-pointer. Less than a minute later, Patton laced another pass out of bounds.

USC forward Terrance Williams II, left, and guard Wesley Yates III, right, try to steal the ball away from Oregon guard Jadrian Tracey in the first half Wednesday.

(Gina Ferazzi / Los Angeles Times)

In a matter of five minutes, Oregon had turned a five-point deficit into a five-point lead. And the Ducks didn’t look back.

“The complexion of the game changes with that,” Musselman said of the two turnovers.

A third consecutive loss elicited questions about the complexion of USC’s first season under Musselman, many of which came from the coach himself. Musselman was always clear about the challenges of building a roster on the fly through the transfer portal. On Wednesday he left little room for interpretation in his assessment.

“We’ve got holes,” Musselman said. “We’re a team that, in order to win a Big Ten game, we’re going to have to play that hard. Then we’re going to have to make some shots. This roster is not picture-perfect by any means.”

USC coach Eric Musselman talks to his team during the Trojans’ loss to Oregon at Galen Center on Thursday.

(Gina Ferazzi/Los Angeles Times)

Prior to its sudden collapse down the stretch, USC actually looked like a totally different team. It clamped down on defense in a way it hadn’t all season, forcing nine first-half turnovers and holding the Ducks to 23 points during the first 20 minutes. USC even won the rebounding battle, which had been its kryptonite through its nonconference schedule.

Before the Ducks got hot late, USC held them to 30% from the field through 32 minutes. But the final eight proved to be the issue.

Point guard Desmond Claude did his best to carry the Trojans across the finish line with a season-high 22 points. USC had little going on offensively aside from Claude, who often was driving into the teeth of Oregon’s defense. Chibuzo Agbo, the Trojans’ best shooter, scored 18 but didn’t make a field goal for the final 28 minutes. He committed four fouls in the second half before fouling out late.

Outside of those two, the rest of USC’s roster scored just 20 points on seven-for-24 shooting. But as Musselman considered where Wednesday went awry, he didn’t hesitate to point to defense that fell apart.

“That was the difference,” Musselman said. “You can’t give up 45 points at home in a half.”

The defense was an issue through most of the first month o. For a while Wednesday, it seemed to iron itself out.

Oregon guard Jackson Shelstad celebrates after making a three-pointer against USC with 4:08 left in the game.

(Gina Ferazzi / Los Angeles Times)

But after a third straight loss, Musselman was left wondering where his defense — and his team — was heading.

“I don’t know how many Big Ten games we’re going to win,” Musselman said. “What I do know is if you put forth that effort from a culture standpoint, you walk out of the building and you think the team played hard. You think the team gave great effort, and you think the team didn’t close the game. Which we didn’t.”

Claude, for the record, wasn’t throwing in the towel just yet.

“It’s a long season,” Claude said. “Everybody is new. We’re still figuring it out. But as a team, we’re still confident that we’re going to go in and do some damage. We just have to stay locked in on defense and stay confident.”