As he sat in the team hotel in Birmingham on the eve of what was tabbed as the "Game of the Century", Reid paced back and forth, unable to crawl into bed and shut his eyes.
His roommate on road trips, fellow defensive back Mo Claiborne, sensed a different Reid than he had known on trips prior.
Claiborne said Reid is usually calm before games, a second-year player with a good poker face in big-game situations.
But Friday night, Reid couldn't seem to shake the thoughts running through his head.
Not with No. 1 vs. No. 2 looming.
"The whole night (Reid) was talking, ‘I have to have a big time game, I have to have a big time game,'" Claiborne said. "I told him, ‘Let it come to you. Just go out and play every snap hard.'"
Following a 9-6 slug-it-out win by No. 1 LSU over No. 2 Alabama, it's safe to say Reid did just that.
Working on minimal sleep, Reid delivered what he called the most memorable game of his career: Six tackles, five in the first quarter, a forced fumble a 26-yard blocked field-goal return and an oh-so-timely interception.
Turns out, Reid was only following orders.
Before the team took the field, LSU coach Les Miles charged his team with one task.
"Coach Miles told our team before the game that the team that wanted it the most would win," LSU defensive coordinator John Chavis said. "I think our kids did. They went out and played that way."
Reid epitomized that.
On the first play of the game, Alabama running back Trent Richardson ran off the left side for an 18-yard gain.
Bryant-Denny Stadium went nuts.
On the next play, Tide quarterback A.J. McCarron found Richardson open in the flat, and Richardson grabbed the pass and went sprinting up the sidelines.
With 224 pounds of man rolling his way, Reid went right at Richardson, delivering a hit that sent the ball flying out of bounds.
Two snaps in, Reid had forced what would be the game's only fumble.
The Tigers didn't recover the loose ball, which shot out of bounds, but the tone had been set.
LSU was going to want it most.
"Any time one of our players comes down and makes big hits, it sparks our whole team," Claiborne said.
Richardson finished the game with 89 yards on 23 carries – statistical evidence of how physical the Tigers got with one of the nation's most physical running backs.
But it wasn't a tackle on Richardson that had Miles talking about Reid in his post-game press conference.
"How about the interception down there on the goal line?" Miles said. "That was smart."
After a Drew Alleman field goal tied the game at 6-6 in the fourth quarter, the Tide took possession and quickly moved the ball to midfield. Two Richardson rushes later and the ball was at the LSU 28-yard line.
Then Tigers' defensive tackle Josh Downs went down with an injury, and the Tide players went back to the bench for water and a quick conversation – giving Alabama coach Nick Saban the chance to dial up a trick play.
Turns out he should leave that up to the Mad Hatter.
Tide receiver Marquis Maze, lined up in the Wildcat formation, took the direct snap, faked the run and pulled up to throw.
Down field, Alabama tight end Michael Williams was running free.
Chavis, who told his defense to expect a pass if Maze was inserted into the wildcat, initially freaked.
"At first when I saw the tight end behind us, I'm thinking, ‘This is not good,'" he said.
Worry not, Chief.
Reid, who said he put in more time studying film than any game week in his life, read the play the entire way.
"That is the key as a safety, if the tight end doesn't block and releases up the field, it's a pass," he said.
"I was covering my guy and I saw the tight end running free, so I knew they were going to go for the touchdown. I just went deep, and thank God I got the ball."
Williams, a 6-foot-6, 269-pound tight end, didn't let the ball go away easily, fighting for the pass in the air and on the ground on a play that was ultimately reviewed by the officials.
"I got my hands on it first and he tried to take it away from me, but I just held on," Reid said with a chuckle.
Reid held on, and after two more Alabama possessions and one overtime, the Tigers held on to their No. 1 ranking and remain in the driver's seat for a trip to the SEC Championship Game.
As promised, this one didn't come easily.
"Bama is the best team we have played this year and the best team I have ever played in my life," Reid said. "This is the biggest game I have ever been a part of.
"I am glad to be a part of it, and glad we got the victory."
There was blood, sweat, tears and five successful field goals.
And of course, there was Reid.