Shortly after Louisville's James Quick was ushered out of bounds three yards short of a comeback victory at Clemson last month, the chatter began. Not everyone was convinced Clemson was better than Louisville.
By virtue of that head-to-head result, No. 2 Clemson would play in the ACC championship and make it back to the playoff if it finishes undefeated. No. 7 Louisville needs help.
"Player for player, they're close talent-wise," an ACC defensive assistant told ESPN. "There is not much separation."
It's so close that it isn't that wild to entertain the notion 7-1 Louisville might be better than 8-0 Clemson. ESPN's FPI would favor Louisville on a neutral field by a point (technically 0.7). Ed Salmons, the Westgate SuperBook's respected chief football handicapper, said their power ratings have Louisville "a touch better."
College football coaches prefer the film to functions and, despite some waffling, side with Clemson. Every coach polled surprisingly stuck with the on-field result, but not because of that 42-36 final score on Oct. 1. The coaches value quarterback Deshaun Watson's demeanor and the Tigers' big-game experience.
But man, is it close, they said.
"Those teams are probably two of the best to compete with Alabama, but I think the experience of Deshaun Watson, without question, has to be a real factor," an ACC head coach said. "I'd probably err [with Clemson], but Louisville is every bit as talented, if not more in some places. But having [playoff experience] is a great advantage."
It's the intangibles separating Watson from his Louisville counterpart Lamar Jackson, coaches said. Against Florida State, Watson never lost his poise, bouncing back from two interceptions to score on each of the Tigers' last three drives.
"Watson has the ability to make those breathtaking plays, but in terms of being methodical and consistent in doing all the right things, that splits those two," said a defensive line coach whose team has played against both quarterbacks. "Lamar Jackson can throw the ball and he's had so many explosive plays, but in our game he pressed a little.
"I don't think I've ever seen Deshaun do that."
An ACC offensive coach said Jackson is tougher to defend, and if he were an NFL coach, he'd draft Jackson. He likes the talent that surrounds Watson more, though. Strip away the quarterbacks, and coaches point to Clemson's receivers and defensive line as the two best position groups.
"The quarterback at Louisville probably makes a bigger difference for them than it does Clemson, and that's tempered with obviously both are tremendous players, but you've got a couple of outstanding running backs like Wayne Gallman and that receiving corps. When they're at full strength, that D-line is pretty special," the ACC offensive coach said.
The Tigers' 31 sacks are one short of Alabama's pace, and they're ninth among Power 5 teams in pressuring quarterbacks. They're eighth among Power 5 teams in stopping rushes for no gain. The defensive line coach said it starts with the front -- a sound, well-coached group routinely put in positions to succeed.
"That might be the thing tipping scales in their favor," he said. "There aren't too many offensive lines that can handle all the different things they throw at you."
Plus, the Louisville offensive line could be its Achilles heel, he said.
Another ACC head coach disagreed: "The way they [Louisville] score points and move the ball, I don't know how many bad heels they got," he said -- but the defensive line coach thinks you a team can take advantage using movement.
Against Virginia last Saturday, Jackson was under duress on 24 percent of his dropbacks and was hit 16 times, including five sacks.
A Power 5 head coach told ESPN's Adam Rittenberg: "Stop [Jackson] and you beat them. People have told me the Cardinals are frontrunners."
Another Power 5 head coach said Clemson is more complete, and the Cardinals have had too many close calls.
An ACC head coach familiar with both teams favors the Tigers, but doesn't believe it's a one-man show for the Cardinals. Two of the ACC's top three rushers in yards per carry join Jackson, who also has Quick, Jamari Staples and Cole Hikutini running pass patterns. The defense is loaded from front to back.
"This Louisville team is freakishly talented. I look at them with my eyes wide open, like, 'Wow,'" he said. "This quarterback is sensational, and the best part is the defense to match it."
However, don't underestimate the pressure of playing catch-up in the rankings, a coach said. Washington, Texas A&M and Ohio State might need to finish with two losses for Louisville to advance, and the Cardinals are in danger of being jumped, too.
A Power 5 assistant coach of a fringe contender in 2015 said the rankings uncertainty wears on players.
"You're fighting for that spot. It weighs in the back of your mind and the kids' [minds]," he said. "You can feel and hear them talking about it on the edge, like, 'How is this going to fit? How is this going to work? Am I going to be kicked out with one loss?' It's tough."
Tougher is a one-score Oct. 1 loss on the road that could end a team's playoff chances. But coaches for now are in agreement that Clemson is better than Louisville.