Brandon Harris and LSU ventured into a packed, hostile stadium for the first time.
The 15th-ranked Tigers and their freshman quarterback fell behind early and never recovered Saturday night in a 41-7 loss to No. 5 Auburn.
"I do not think the crowd affected us, but the position of being in a big time game may well have affected us," LSU coach Les Miles said.
LSU (4-2, 0-2 Southeastern Conference) has dropped its first two SEC games for the first time in coach Miles' decade-long tenure.
Harris completed 3 of 14 passes for 58 yards in his first start before getting replaced late in the third quarter by Anthony Jennings.
Auburn's Nick Marshall, meanwhile, passed for 207 yards and two touchdowns and ran for 119 and two more scores.
Auburn (5-0, 2-0) dominated from the start on a week when No. 2 Oregon, No. 3 Alabama and No. 4 Oklahoma were upset. The 41 points equaled Auburn's highest total in the rivalry — set with the same margin in the 1999 game.
"Nick played like one of the better quarterbacks in the entire country," Auburn coach Gus Malzahn said.
And Auburn played like one of the better teams.
With Marshall playing again like the Heisman Trophy candidate many expected him to be, Auburn could rise to the No. 2 spot it held after last season.
He completed 14 of 22 passes, had 16 carries and supplied a steady diet of big plays. Marshall threw touchdown passes of 56 yards to Sammie Coates and 9 yards to tight end C.J. Uzomah, and scored on runs of 7 and 29 yards.
Cameron Artis-Payne ran 24 times for 126 yards and gained 35 yards on three catches. Coates had his first big game of the season with 144 on four catches.
Auburn outgained LSU 566-280, the most yards it has produced in the series. LSU had won the past three meetings but couldn't muster much fight in this one and is likely already out of the hotly contested SEC West race.
"This felt different. Everything felt different," Malzahn said. "Our players, our coaches, myself. It was just a big game."
Miles sent in the former starter Jennings to replace Harris late in the third quarter, but the results didn't change dramatically. Neither quarterback managed to convert any of their combined 13 third-down attempts.
Harris had led LSU to touchdowns on nine of his previous 10 drives but a 52-yarder to fellow freshman Malachi Dupre and a 36-yard run were his only real highlights in his first game before a hostile crowd.
The long pass set up Kenny Hilliard's 1-yard touchdown run late in the first quarter in a freshman-sparked drive with the Harris-to-Dupre strike and the runs of Leonard Fournette.
LSU offensive lineman Vadal Alexander said Harris can grow from the experience.
"It's going to help him in the long run," Alexander said. "He's going to learn a lot from this. This is probably the most hostile environment you can have as a player in the SEC, in the country really. It's a learning experience and he's going to learn from it."
Jennings was 5-of-10 passing for 84 yards after struggling against New Mexico State a week ago. Miles said he hadn't made a decision on his starting at Florida.
"We kept putting the defense on the field," he said. "We tackled, we played hard, but offensively we did not execute. We are a work in progress. Certainly a group of men that are committed to fixing things. But frankly we did not get it done."
Jennings came in with LSU down 34-7 after Marshall lost a fumble at his own 35. The result was more of the same: four plays, no first down.
Fournette gained 42 yards on 10 carries. Leading receiver Travin Dural had one catch for 40 yards.
The tone was set early.
Marshall led scoring drives on each of Auburn's first four possessions, while LSU failed to get a first down on five of its opening six.
Auburn raced to a 31-7 halftime lead, the most the program had ever scored in a half against LSU. The 247 first-quarter yards was also the high mark in any quarter under coach Gus Malzhan.
"We came out fast, we came out hard and kind of asserted ourselves early in the game and kind of had them on their heels the whole time," Uzomah said. "I feel like that's a testament to where we are as a team."