ATLANTA — Playing its first game since Kevin Knox left for the NBA draft, Kentucky got overwhelmed Tuesday by Duke’s freshman power trio — one of whom could be Knox’s teammate next season.

Zion Williamson, RJ Barrett and Cam Reddish led Duke with their brilliance to a stunning 118-84 romp over John Calipari’s Wildcats, and Knox watched every minute from his hotel room in Atlanta, calling it “painful.” Knicks GM Scott Perry and president Steve Mills were at the game.

The Knicks’ 2018 lottery pick knows well that Williamson, Barrett and Reddish stand to be high lottery picks next June — if not the top three picks judging by Tuesday.

Knox, who will play his second game since hurting his ankle, called them a “three-headed monster.” He branded Duke the favorites to win it all, though he won’t give up on Calipari’s group. Duke was ranked only fourth entering the season in the polls while Kentucky was No. 2.

“They impressed me a lot,” Knox said at the morning shootaround in Atlanta. “I know most of them from high school playing against them sometimes. I’m cool with all of them. Those are my guys. They looked really good. They were really aggressive in their first college game. I was very definitely impressed by their performance.”

The Knicks, who have the league’s youngest team, are 3-8 and likely headed toward another lottery, especially with coach David Fizdale’s vision; he recently said he’s not “chasing victories.”

Calipari restocked after losing one-and-done Knox and Shai Gilgeous-Alexander, both lottery picks. Calipari’s string of lottery picks could be over — with combo guard Keldon Johnson having the best Kentucky chance.

“Kentucky had a shot before the game, but I‘m pretty sure Duke is the favorite now to win it after watching that game,” Knox said. “But this is the first game. They shot really well last night, but I don’t know if they’ll shoot like that every game.

“They got a three-headed monster that’s going to produce every single night. That’s one thing about having more than one star. You don’t know who’s going to show up. Duke is probably the favorite now after last night’s game, but I still got my Kentucky boys and one loss is nothing. Last night’s game won’t determine the championship or who will make the Final Four.”

Knox, meanwhile, is ready for regular backup minutes. In his return from a seven-game absence, he played five first-half minutes in a double-overtime loss to Chicago on Monday.

“After the game I didn’t really feel it at all,” Knox said about his ankle. “I got my ice when I got to the locker room and felt good the next day. I try to keep stretching it out. It’s going to be sore after some games.”

Fizdale said of Knox, “I’m going to have him in the mix.”

Fizdale didn’t take in the Zion Show. Williamson scored 28 points, Barrett 33.

“I was too busy watching my own misery,” Fizdale said.

Bernard King, who lives in Atlanta, was the latest alum to take in a Knicks shootaround and speak to the team. King huddled with Knox afterward. Fizdale hopes to build a King/Knox bond.

Tim Hardaway Jr. will start Wednesday against his former team after missing one game with back pain.