TALLAHASSEE, Fla. -- With star forward Zion Williamson out and No. 1 Duke trailing Florida State with 2.8 seconds remaining, coach Mike Krzyzewski drew up a play for one of his other talented freshmen to make.

The Seminoles anticipated it would be R.J. Barrett. But it turned out to be Cam Reddish, left wide open to make the game-winning shot. When the uncontested 3-pointer swished through with 0.8 seconds left, Duke celebrated an 80-78 come-from-behind victory -- one that remained in doubt until the final second.

For Reddish, it was a redemptive moment after a six-game stretch in which he hit a bit of a shooting slump. But with 23 points and the game-winner on Saturday against the No. 13 Seminoles, Reddish showed not only the world but himself that he knew how to find his way out of it.

"It's a blessing," Reddish said. "I've worked so hard to get here. I was praying like crazy, trying to get back to myself. I'm just glad I was able to make that shot."

Williamson left the game late in the first half after he got poked in the left eye. After experiencing double vision that did not clear up by the start of the second half, Duke knew it would have to play without him. Florida State took advantage inside with the big-bodied Williamson out, and the Seminoles made it their mission to score easy baskets in the paint.

That strategy worked -- Florida State had seven dunks in the second half and 10 total in the game, the most Duke has given up all season. The Seminoles had their outside game working, too, and so did Duke with Reddish and Barrett leading the way.

Both teams went back and forth in front of a raucous crowd at Florida State, loud enough to draw praise from players and Krzyzewski afterward. The Seminoles took a 78-76 lead with 15 seconds remaining that had the crowd on its feet.

Cam Reddish, right, finished with 23 points, including a 3-pointer with 0.8 seconds left to lead No. 1 Duke past No. 13 Florida State. Melina Myers/USA TODAY Sports

Barrett had a chance to tie the game when he got fouled and went to the line. But he only made one free throw. Phil Cofer got the rebound and tried to knock it out of bounds off a Duke player. But after review, officials said the ball went out of bounds on Florida State, giving the Blue Devils another chance at the win.

The teams traded timeouts, and Krzyzewski said he changed plays before settling on the final option.

"Coach said it," Barrett said. "He said, 'They're going to watch me and Cam's going to be wide open."

Added guard Tre Jones: "We knew they'd be trying to not let R.J. get the ball. We're going to him down the stretch. On that last play, we drew it up so R.J. would come off, and if he wasn't open, Cam was right behind him and one of them would be open. Coach drew it up, and the play was wide open and Cam was able to execute."

Reddish and Barrett were stunned that he was left all alone. So was Florida State guard Trent Forrest, who said simply, "Somehow, we lost Cam Reddish."

Said Florida State coach Leonard Hamilton: "I didn't expect them to get the ball at the elbow; I thought we had that covered. I expected them to get the ball inbounds, but not a direct pass out of bounds to a guy at the elbow. They did a very good job of creating some misdirection. I gotta go back and look at the film and see how he delivered that pass right on the money -- 'cause we had a 7-foot guy right on top of the ball, and I thought that would be enough for them to at least have to go in another direction with that short amount of time on the clock. Great execution by them, and great finish by a very good player."

Earn Everything An all-access series documenting the Blue Devils' preparation for the 2018-19 season, exclusively on ESPN+. Watch on ESPN+

Reddish and Barrett combined to score 55 points, tied for their most this season (also combined for 55 vs. Kentucky in the Champions Classic). They combined to go 9-of-15 from behind the arc.

With Williamson out, both players knew exactly what they had to do to lead Duke to the win. And perhaps it was good for them to be able to lead the Blue Devils, with so much of the spotlight going to Williamson this season. But Krzyzewski said It wasn't as if they had something to prove.

"Prove is not the word," he said. "They rose to a different occasion."

Krzyzewski said that Reddish was fighting cramps the entire second half as well.

"It's a huge game for him," Krzyzewski said. "Whenever a kid hits a game winner like that, it's storybook. Our guys, this is our 15th game. A number of those guys, they've never been in an experience like this -- in this atmosphere, against that level of talent and expertise. And to come up -- it wasn't just that he hit that shot; he hit a couple other big ones. R.J. kept us in it, with Tre making sure we were at least getting the ball to those two guys. But, huge -- huge for Cam."

Huge for a young Duke team moving forward, too.