ATLANTA — It had been 392 days since the Panthers last lost a regular-season game.
But cornerback Josh Norman hadn't forgotten what it felt like.
"Guys are not used to losing," Norman said in a quiet visitors locker room at the Georgia Dome. "It kind of (stinks), man."
The Panthers' run at perfection came to an end in the cavernous dome where they'd clinched the NFC South the past two seasons. But after a 20-13 loss on Sunday, there were no "division champs" hats being passed out or music blaring in the locker room — just a lot of downcast players trying to figure out where it went wrong.
And while the offense failed to muster another touchdown after its opening drive, the defense gave up 373 yards to a team it throttled in a 38-0 shutout on Dec. 13 in Charlotte.
"I think we were just purely outplayed," strong safety Roman Harper said. "And we couldn't come out there and win at the end. That's all we've done, is find ways to win all year, and we couldn't do that (Sunday)."
Panthers coach Ron Rivera won't have to answer questions about playing his starters next week against the Bucs. After Arizona beat Green Bay on Sunday, the Panthers need to win or have the Cardinals lose to Seattle next week to clinch the top seed in the NFC playoffs.
The Falcons' big play was a killer: A 70-yard touchdown catch by Julio Jones that quarterback Matt Ryan kept alive by rolling out of the pocket and motioning for Jones to go deep.
Jones had two defenders around him. But free safety Kurt Coleman fell and Jones outleaped middle linebacker Luke Kuechly, who said he mistimed his jump. Jones' score gave the Falcons a 14-10 lead late in the third quarter, and the Panthers never led again.
Carolina, the fourth team ever to start 14-0, got the ball with 90 seconds left and no timeouts. Cam Newton completed a 19-yard pass to Corey Brown on first down but fumbled when stripped by defensive end Vic Beasley on the following play. Former Bucs defensive lineman Adrian Clayborn recovered for the Falcons, wrapping up the win.
"I viewed this game as a measuring stick for us," Atlanta coach Dan Quinn said. "I wanted to see how our team would respond after the game up there."
Ryan threw for 306 yards and one touchdown for the Falcons. Former Florida State running back Devonta Freeman ran for 73 yards and a score.