TUSCALOOSA, Ala. -- Blake Sims passed, ran and confidently staked his claim as the leader of No. 3 Alabama's offense.

Sims threw for two touchdowns and rushed for a third in three quarters and emerged as the Crimson Tide's undisputed starting quarterback -- for now, at least -- in a 52-12 victory over Southern Miss on Saturday night.

"I didn't feel real comfortable with the way the game was going, and it just didn't feel right to make a change," Alabama coach Nick Saban said. "Do we want to continue to play both quarterbacks and try to develop both guys? Absolutely.

"Jake (Coker) needs to play and he needs to develop confidence. I think we're going to have to make a decision on a week-to-week basis on what gives us the best opportunity to win. Right now, Blake probably is a little more confident. If that remains that way, he's probably going to start the game. He's started every game so far."

Sims was 12-of-17 passing for 168 yards for the Crimson Tide (3-0) ahead of the team's Southeastern Conference opener against Florida. Coker didn't come in until late in the third quarter against the Golden Eagles (1-2), who have lost 25 of their last 27 games.

"Everybody knows their time to step up because you get that feeling," Sims said. "It doesn't matter if you're a freshman, sophomore, junior or senior, if you've got to step up, you step up at the time."

Most of Sims' completions went to the nation's leading receiver, Amari Cooper. Cooper had eight catches for 135 yards and a touchdown to tie DJ Hall's school record of five consecutive 100-yard games set in 2006. Kenyan Drake scored three touchdowns and produced 59 yards on nine rushes.

Sims also ran five times for 46 yards, including a 4-yard touchdown. Coker did open by leading Alabama on a 99-yard scoring drive.

"Obviously, Blake is our starting quarterback right now," Cooper said. "He's playing more than Coker's playing, and he's playing well. Both of them are playing well."

Nick Mullens completed 19 of 35 passes for 207 yards to lead Southern Miss.

Corey Acosta had field goals of 33, 43, 37 and 30 yards to account for all the points by Southern Miss.

Alabama outgained the Golden Eagles 547-263 in total yards, allowing just 56 rushing yards. The Tide ran for 333 yards, led by Derrick Henry's 11 carries for 73 yards.

"It's hard to run against them," Southern Miss coach Todd Monken said. "They've got big guys up front. It's hard to push those guys around."

Cooper accounted for 108 of Sims' 123 passing yards in the first half. He moved past Ozzie Newsome into the Tide's No. 3 spot for career receiving yards.

Coker got into the game with 2:10 left in the third quarter with Alabama at the 1. He completed all three of his attempts for 36 yards before Drake scampered 29 yards for his third touchdown and a 42-9 lead.

Coker finished 5-of-7 passing for 46 yards. His third-down sack forced Alabama to settle for a 30-yard Adam Griffith field goal.

The Florida State transfer and Sims had battled through preseason camp and split time in a rout of Florida Atlantic. Sims played all but the final minutes of the opening win against West Virginia and didn't leave this one until it was well in hand either.

Southern Miss scored field goals on its first and last drive of the opening half, but managed just 4 yards in the second quarter.

Two of Acosta's kicks were set up by Alabama mistakes.

Tyler Sarrazin's punt bounced off Alabama's Tyren Jones, giving the Golden Eagles the ball at the 29.

They couldn't get anywhere but Acosta got them three points, and he added the 37-yarder in the third quarter on a drive kept alive by safety Nick Perry's targeting flag on a third-down incompletion.

Perry will miss the first half of the Florida game. He posted an apology to Alabama fans on his Twitter page before the quarter was done, saying that "My boys will take care of business."

"I don't question the call that was made against Nick Perry," Saban said. "I don't think he did it intentionally but was it helmet-to-helmet? It probably was. I was standing right in front of it."