It was supposed to be LSU’s one strength on defense.

When LSU rolled into Jordan-Hare Stadium on Saturday evening, it boasted the No. 1 pass defense in the Southeastern Conference. LSU had the fifth-best secondary in the nation, allowing only 130.6 yards per game through the air.

Then it played Auburn.

The home squad knew of LSU’s weakness: the visiting Tigers ranked No. 12 in the conference in run defense, surrendering 161.6 rushing yards per game. Opposing squads averaged 4.5 yards per carry against LSU.

Considering Auburn’s typical offensive game plan, it was the perfect matchup.

Sixty-one percent of Auburn’s play calling through its first four games of the season consisted of running the football. Fifty-four percent of its offensive yards were gained on the ground.

On Saturday night, though, Auburn took to the skies early and often.

It began with just over seven minutes remaining in the first quarter. With Auburn leading 3-0 and looking for a spark, senior quarterback Nick Marshall dropped back, took one look, then fired to a covered Sammie Coates just in front of the end zone.

Coates was blanketed by LSU sophomore cornerback Rashard Robinson, who had become a critical piece of the Tigers’ secondary after being a lock-down defensive back in 2013.

“I don’t care who I’m going against,” Coates said. “If (Robinson) stopped me, then he stopped me, and I’d give him props. I went out there tonight and just took advantage of every chance I got to make a play.”

Robinson leaped to knock the pass away from Coates, but he whiffed, leading to a 56-yard score to put Auburn up by 10.

It was only the beginning of Auburn’s dissection of LSU’s defensive backfield.

“It energized us a lot,” Marshall said. “Last year, we’d heat up, and then we couldn’t put the other team away. Today we focused on it. … And we put our feet on the gas and kept on going.”

The home squad didn’t even need its starting quarterback to impose its will on the visiting secondary.

On second down with roughly 4:30 remaining in the first quarter, Auburn ran an end-around, and sophomore passer Jeremy Johnson found the ball in his hands with an open Coates streaking down the field.

Johnson found his man for a 38-yard gain after Coates fought off LSU junior safety Jalen Mills. Marshall would rush for a touchdown later in the drive.

Marshall added one more passing touchdown to the stat sheet before halftime, hitting a wide open C.J. Uzomah in the end zone.

In the first half, Marshall completed 12 of 16 pass attempts for 182 yards and two touchdowns. Coates had three receptions for 123 yards and a score.

The loss of LSU sophomore defensive back Dwayne Thomas was more than evident. Used heavily in the “Mustang” package, Thomas was a constant threat both in the backfield on blitzes and in the short passing game. Thomas tore his ACL in LSU’s previous game against New Mexico State, ending his season.

Marshall was able to make the most of a battered secondary, completing a number of passes to senior running back Cameron Artis-Payne, who had three receptions for 35 yards.

An Auburn passing game that formerly ranked No. 11 in the conference continued to have its way in the second half.

The Marshall-Coates connection stayed red hot in the third quarter as the duo hooked up on a 21-yard pass play that led to an Auburn field goal.

Auburn’s senior passer finished 14-of-22 for 207 yards and two touchdowns. Coates had four receptions for 144 yards and a score.

Not even a No. 1 secondary could slow the eventual rout by the home Tigers.

“That’s one thing we can do,” Coates said. “We’ve got too many playmakers on offense. I don’t care who we play against. We’re going to make plays regardless.”