ORLANDO, Fla. -- LSU coach Brian Kelly said his team's 45-24 loss to Florida State on Sunday night was "a total failure," after a second-half collapse allowed the Seminoles to run away with the game.

The No. 5 Tigers had a 17-14 halftime lead but allowed No. 8 FSU to score 31 unanswered points in the second half. They had no answers for Noles quarterback Jordan Travis (342 yards passing, five total touchdowns) or wide receiver Keon Coleman (122 yards, three scores).

The loss marked LSU's largest defeat as a ranked team in a season opener in the AP poll era (since 1936).

"This is a total failure from a coaching standpoint and a player standpoint that we have to obviously address and we have to own," Kelly said. "I know adversity is always going to strike at some time in this game, and this is our first real piece of adversity that we have to address. I'm confident our guys and our coaches will rally in the manner that they need to."

LSU had plenty of opportunities in the first half to build a much bigger lead but squandered them. On the opening drive of the game, the Tigers had four tries from the 1-yard line but failed to score on fourth down after quarterback Jayden Daniels was sacked. LSU had another chance in the second quarter on fourth-and-goal from the 1, but Daniels was stopped again.

Kelly said both were "standard fourth-down calls and decisions." Despite the inability to score from the 1, LSU racked up yards in the first half and led 17-14 at halftime. But after the break, Florida State imposed its will and began to overpower LSU up front.

"The buck stops with me, and I've got to get our football team to understand and recognize that you've got to play this game for four quarters with a mentality," Kelly said. "We just did not, for some reason. We thought we were somebody else. We thought we were the two-time national champion Georgia Bulldogs or something. I don't know what we thought, but we were mistaken."

On Thursday, Kelly made headlines when he said on his opening radio show of the season, "We're gonna go beat the heck out of Florida State." Whether those comments resonated in the Florida State locker room is unknown; both Coleman and Travis said they were unaware of them when asked in their postgame news conference.

What is clear is that Kelly needs to find a way to get his team to play a complete game.

"How do we handle this? Is this who we want to be, or do we look at this and say this isn't the kind of football team we want to be," Kelly said. "When you have those kinds of losses, they are disappointing, and in some instances, they are devastating losses, but it's how you respond to them. They have a chance to respond to this very disappointing performance in the second half.

"So the choices they will have to make will be ones that start tomorrow."