Before Caleb Williams emerged as the likely No. 1 overall pick out of USC in the upcoming NFL draft, he was Oklahoma football's backup quarterback to Spencer Rattler.

Most Sooners fans know the story of how Williams supplanted Rattler in the 2021 Oklahoma-Texas rivalry game, led the Sooners to a 21-point comeback win at the Cotton Bowl and kept the job for the rest of the season before following former coach Lincoln Riley by transferring to USC.

Fast forward to 2024, where both Williams and Rattler — who spent his final two college seasons at South Carolina — are both expected to be selected in the upcoming NFL draft. Prior to likely becoming the Chicago Bears' hopeful franchise quarterback, Williams looked back on his time as a backup at Oklahoma on a recent podcast appearance.

"That one was real tough for me," Williams said recently on the Pivot Podcast. He was then asked why it hurt when he wasn't named the starter before the season.

"Because I was the best in the country," he replied.

"I told many people before I went there, and there's a backstory to it all of why I was so fired up," Williams continued. "I told people before I went there that I was going to start and play and beat (Rattler) out. I thought I beat (Rattler) out in spring, and he was projected No. 1 and all that, so he started for six games. And so, I prepared. Lincoln told me, 'Keep going.' And that's something I didn't understand. Those two words I did not understand when he told me because I wasn't asking him, I wasn't going to him to beg for playing time.

"But I came to him and asked, 'How do I do it? How do I beat this dude out.' Because he never let me get reps with the first team. Never let me get reps with the older guys. I took advantage of my reps, I got after it, put my head down and at a certain point I felt like I beat him out. ... At the time. I was so angry, so frustrated because I didn't feel like that was what I wanted to hear because I felt like I was the best, I felt like I could've helped us win all the games, gotten more reps during the season and I'm ready for those moments later in the season.

"I kept preparing the best I could so that when I had my moment, there was no way that he was ever getting it back."

Caleb Williams talks Spencer Rattler, Sooners football on podcast

Here's the full clip of Williams looking back on his freshman season at Oklahoma, where he was the backup before replacing fellow 2024 NFL draft quarterback Rattler at midseason:

Caleb Williams NFL draft projections

Here are the latest NFL draft projections for former Oklahoma quarterback Caleb Williams:

• USA TODAY Sports: First round, No. 1 overall to Chicago Bears

• NFL.com: First round, No. 1 overall to Chicago Bears

• The Ringer: First round, No. 1 overall to Chicago Bears

• The Athletic: First round, No. 1 overall to Chicago Bears

This article originally appeared on Oklahoman: Caleb Williams did not like backing up Spencer Rattler at Oklahoma