BATON ROUGE, La. — Demetrius Byrd waved up at the press box, hoping LSU offensive coordinator Gary Crowton had seen what he saw.

With time expiring on LSU's national title hopes, Byrd wanted a chance to beat the lone defender on his side of the field.

"Then I got in the huddle and that was the play call, and I knew I just had to go out there and make a play on it," Byrd said

With a second to spare, Byrd hauled in Matt Flynn's 22-yard fade to the back of the end zone, lifting fifth-ranked LSU to a 30-24 victory over No. 18 Auburn last night.

A week after losing in triple OT to Kentucky and giving up the No. 1 ranking, LSU couldn't afford a second straight loss.

Now with South Florida losing to Rutgers on Thursday, LSU (7-1, 4-1 Southeastern Conference) is certain to move up to at least third in the BCS standings, behind only undefeated Ohio State, which also won, and possibly Boston College, which was idle this weekend.

The victory also puts LSU on the inside track to win the SEC West, as the winner of the Auburn-LSU rivalry has done in five of the past seven years.

Flynn finished with 319 yards passing and three touchdowns, the last on what seemed to be a risky play called by a coach who's shown he's not afraid to gamble.

Coach Les Miles' offense had converted five fourth downs in a dramatic 28-24 victory over Florida the last time LSU was at home. This time, he let Flynn take one last shot at the end zone with the clock winding down, when the safer play would have been to set up for a potential game-winning field-goal attempt.

LSU had a timeout left, but the Tigers cut it awfully close on their final play.

"If we tip the ball in the end zone, the game's over," Auburn defensive coordinator Will Muschamp said. "They made the play."

Miles said those calls come from being confident in his players, who had come back from a 17-7 halftime deficit.

"They showed great character and great resolve and want — the way they played in the second half," Miles said.

Auburn's Brandon Cox turned in a gutty performance, passing for 199 yards and a pair of touchdowns.

His last scoring pass, a 3-yard strike to Rod Smith, gave Auburn a 24-23 lead with 3:21 to go, completing an 83-yard drive.

Auburn (5-3, 3-2) squibbed the kickoff, giving LSU the ball on its 42.

Flynn scrambled for 19 yards during the final drive, then took one more shot at the end zone instead of getting the ball in the middle of the field to set up a field-goal attempt. He floated a pass perfectly to the back of the end zone, where Byrd emerged from behind defensive back Jerraud Powers and made the catch, sending Tiger Stadium into a frenzy.