USC coach Lincoln Riley intimated that his decision to fire defensive coordinator Alex Grinch hadn't been made yet when he left the Coliseum on Saturday night after the Trojans' 52-42 loss to Washington.

But he watched the game again that night -- all 572 Huskies yards -- and decided to sleep on it.

"Thought about it a lot throughout the night. Didn’t sleep much. Thought about it a little bit more Sunday morning, and just felt like it was in the best interest of our program, both for this year – because we still have a lot to play for, we still have a really cool opportunity in front of us – and for the future that we needed to make the change," Riley said. "Just, we simply weren’t making the progress I think that we all expected we would make."

A day after dismissing Grinch, who had been with him for three seasons at Oklahoma and two years here at USC, Riley addressed the decision and its timing with reporters Monday after practice, taking questions for 12 minutes surrounded by the largest assemblage of TV cameras and media that has shown up to campus all season.

As he noted in his first comment, USC (7-3, 5-2 Pac-12) can still play its way into the Pac-12 championship game if it can upset No. 6 Oregon (8-1, 5-1) on the road this week and beat rival UCLA in its regular-season finale.

For that reason, Riley said the majority of his focus will be on preparing and coaching the team these next two weeks before he turns his full attention to scouting and pursuing a defensive coordinator hire.

"We’ve got a big-time challenge and a big-time opportunity right in front of us here with these last two games. Win these two, we can put ourselves in a pretty cool position," Riley reiterated. "So that’s our focus, my focus going forward. If we were in situation where we didn’t have a whole lot left to play for in terms of a conference championship, having an opportunity there, might feel a little bit different. But we’re still – we’re very laser-focused on these opportunities ahead. Whatever comes next after that, we’ll deal with it at an appropriate time."

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Asked if there was any input from athletic director Jen Cohen or others that factored into the Grinch decision, Riley responded concisely, "It was my decision."

And it was clearly a tough one personally for him.

The last time Riley was in need of a defensive overhaul, it was Grinch he turned to after firing defensive coordinator Mike Stoops at Oklahoma early in the 2018 season.

The Sooners finished that 2018 season 114th in total defense (453.8 YPG). In Grinch's first season in 2019, the Sooners ranked 38th (356.4) and then 29th in 2020 (350.6).

It wasn't quite as good in 2021 as Oklahoma's defense ranked 76th (390.8), but Riley was convinced he had the right guy for the job. When Riley took the USC job, Grinch was one of two assistant coaches on the plane with him to Los Angeles the next morning.

Riley talked Monday about how close his and Grinch's families and children are and the personal toll of making this decision.

"Sucks. Yep, it sucks," Riley said. "I've been very lucky, I've had great staff members in the time I've been a head coach that have supported me, Alex being one of those. We won a lot of games, a lot of championships, did a lot of great things together. And it's not easy. He's a good friend, he's got a great family, our kids are close, you know? Like, there ain't -- there ain't nothing easy about it.

"You can't, as much as you wish you could, sometimes it's hard to separate professional from I think basic human feelings about one another and our families. I knew it was a decision that was the right decision at this time and point, and it certainly didn't make it easy, but I am that committed and we're all that committed to playing great defense here. And whatever it takes to get that done, that's what we're gonna do."

No matter how bad things got with the USC defense late last season or over the last seven weeks of this season, Riley had always remained resolute in his confidence (and defense) of Grinch, accentuating the positives and how close the Trojans were to putting it together. When questioned after the 48-41 win at Colorado, after a second-half defensive collapse that threatened a once lopsided lead, why the defense had the same issues as last year despite the upgrades in talent and depth he had touted, Riley said that was an errant perception by "untrained eyes" who couldn't see what he and the staff saw.

But in the end, Riley was forced to see what fans and critics had been watching for largely since the final weeks of last season when the Trojans got bulldozed by Utah in the Pac-12 championship game and sustained a colossal collapse in the Cotton Bowl loss to Tulane.

While there were some brighter moments -- mostly last season and very early on this season --the numbers told the story all along.

Last year, USC gave up its most yards per game in program history -- 423.9, which well exceeded the previous most (408.9 in2021). This season, the Trojans are now giving up 436 yards per game (119th out of 130 FBS teams) and a program-worst 34.5 points per game (121st). The last six games have been statistically the worst defensive stretch in program history, as USC has given up 44.2 PPG and 483.7 YPG in that span while losing three of its last four games. (The yardage numbers would be even worse if not for the outlier of allowing 251 yards to Notre Dame despite losing 48-20 as the Irish worked with short fields and scored defensive and special teams touchdowns, limiting its offense's time on the field.)

"The bottom line is it didn't get to where he, I, any of our players, any of us expected, and we all take ownership in that," Riley said. "Listen, that's the nature of the beast here. I certainly am not and our players, the rest of our staff are certainly not laying all the blame at Alex. Because the reality is, I have a role in that, the other defensive assistants have a role in that, our players have a role in that, our other staff members. Everybody has a role in it, so if it goes well, that's great, and if it doesn't go up to the expectations then changes are going to be made, adjustments are going to be made and that's just part of the business.

"I have some thoughts of why [it turned out this way] -- don't know that this is the appropriate time to jump into all that when we're getting ready to go play a really important football game. But obviously, once the season wraps up and we look forward to preparing for next year and the future, those are questions that we'll have to answer to make sure that we're heading in the right direction obviously for the future of this program."

Riley also wouldn't disclose which of the co-interim defensive coordinators -- DL coach Shaun Nua or LBs coach Brian Odom -- will call the defensive plays, noting that it doesn't make sense to give Oregon that information ahead of this game.

Nor did he want to get into what he's going to prioritize in the next defensive coordinator.

"I definitely get the question. Honestly, just with the week ahead, I really the next couple of weeks ahead don't know that I want to just start laying out a bunch of specifics," he said. "I know obviously I will. Obviously, in the last several hours I've spent a little bit of time thinking about it – the majority of my time is obviously getting ready to go play Oregon. I think very simply put, though, what I said before, our goal here is to be an elite defense. One that is a huge part of this team, is the strength of this program, is one that leads us to championship opportunities year in and year out. And finding the right person to help get that done is certainly where we'll start."

He reiterated that "99 percent" of his time will be focused on coaching the team the next two weeks and not yet on the coordinator search.

He is mindful of the transfer portal window opening next month and of the early signing period in mid December for high school prospects and how it would help to have the staff settled in advance of that key recruiting stretch, but ultimately it won't force urgency upon the process, he said.

“It’s something you’re aware of. You can’t avoid it, but I’m not gonna sacrifice anything for getting the right person," Riley said. "That’s the most important thing, because these are decisions that have long-ranging impact on our program, and it’s a decision you don’t make lightly in the first place. And as we decide future course, we’re obviously not going to take that lightly either. And so we’ll pay attention to obviously the recruiting, and how that goes and communicating with our recruits, which we’ve had a chance to do a lot to this point and will do more. But nothing will trump getting the right person in here, because we’re gonna play great defense here. Like, period. It’s gonna happen. It’s gonna happen soon.

"There’s no reason why it can’t, and obviously, the key is getting that next person in here, but also the key is all of us, like I said, myself, players, other staff members, everyone that’s a part of this thing going forward has got to own their part in it as well."

He closed his comments Monday by doubling-down once more on his confidence that USC will build the kind of defense it needs to compete nationally.

"I have complete belief, conviction, we will play great defense here. It is going to happen," Riley said. "There’s not a reason in the world why it can’t. We’ll continue to take the steps we have to do to do it and we’re going to be very aggressive that way."