All Lincoln Riley had to do was say yes, take a three-hour flight, change the shade on his red tie -- from crimson to cardinal -- and he was suddenly in sunny, 75-degree late November weather, standing inside the Los Angeles Memorial Coliseum Monday afternoon being introduced as the 18th head coach in USC football history.

"Wow, is this real? Unbelievable," Riley said, turning around to take in the Los Angeles skyline on one side, the Hollywood sign on the other. "It's a surreal moment, to be honest."

The overnight hire of Riley away from Oklahoma that reverberated throughout the sport gave way to a celebratory shock Monday. While Riley pinched himself, USC's administrators and power brokers basked in the glory of a statement hire while remaining surprised they found themselves here in the first place.

"It was never our goal to change the landscape of college football with one of the biggest moves in the history of the game," USC athletic director Mike Bohn said. "But we did exactly that."

Bohn's confidence was palpable throughout the ceremony and afterward too. He called USC the "sleeping giant" that had been awakened.

At Oklahoma the last five seasons, Riley has helmed a team that's had three College Football Playoff appearances, four Big-12 titles and four 10-win seasons, while developing two Heisman-winning quarterbacks in Baker Mayfield and Kyler Murray. USC, meanwhile, has failed to make the College Football Playoff, won only one Pac-12 title and gone 33-23 in that span.

"We felt pressure," Bohn said, noting that his peers are often telling him that "when USC is good, it's good for college football."

USC had been linked to several candidates since they fired Clay Helton back in October. But not once had Riley's name come up. On Saturday night, Riley was asked about his name coming up in LSU coaching rumors. "I will not be the next head coach of LSU," he said. USC, however, was a different story.

"It was tough to leave the place I left," Riley said when asked about Oklahoma. "But at the same time, I knew this was the right thing." When asked later about the sentiment that Riley left Oklahoma because of their impending move to the SEC, Riley said it had "zero impact" on his decision.

"People are going to say what they're going to say," he said.

To hear Riley, Bohn and USC's chief of staff Brandon Sosna tell it, the process to hire Riley was a high-wire act that involved months of work, multiple consultants, over a dozen vetted candidates, roughly 400 pages of data and a 50-slide presentation that USC showed to key influencers as part of their search process.

It all culminated on Saturday night, as Sosna paced inside a suite at the USC-BYU game while the Oklahoma-Oklahoma State game was on one of the screens. As the result of the game went down to the wire, they knew that it could swing Riley's decision or at the very least delay it.

"It came together quickly. But to be honest, in this day and age, in college football, it kind of has to," Riley said. According to him, USC reached out Sunday morning with real interest and they were able to jump on a Zoom call where they made their final pitch to Riley. Within a few hours, the move was made official.

"Everything intrigued me," Riley said. "The location, the history of the program, the opportunities here to recruit, to build a national championship level roster. The opportunity for my family to live in a new place."

In his news conference Monday, Riley also announced that Oklahoma's Alex Grinch will be the new USC defensive coordinator, while Clark Stroud, Denis Simmons, and Benny Wiley will assume the director of football operations, wide receivers coach and head strength coach, respectively.

"These guys got on a plane with me this morning without a contract," Riley said.

While Bohn refused to get into contract details, he did say that the financial commitments "include a competitive spirit" that matches Riley's. "We understand the competitive nature of what's going on in the marketplace," Bohn said. Riley, for his part, said the alignment USC exhibited and the support he received made the decision easier for him.

Even though USC has one game left in its season -- a postponed matchup against Cal Saturday that will be coached by interim Donte Williams -- Riley said he'll get to work in the shadows on recruiting right away with early signing day a few weeks away. Several 5-star Oklahoma commits with West Coast ties have already decommitted from the Sooners in the past few days.

"We plan on building the best roster in the country, and inside that locker room, the best culture in the country," Riley said. "[The Coliseum] is gonna be full. This will be the Mecca of college football."