Flip a coin, says Josh Pastner.

The Georgia Tech head coach is torn over who will become the better NBA player of the Duke tandem: Zion Williamson or RJ Barrett.

In fact, Pastner said in talks with NBA personnel, some consider Barrett, the 6-foot-7 swingman from Canada, a better NBA prospect than Williamson.

Of course, Pastner knows reality. No matter what, Williamson, the 6-foot-7, 285-pound lefty, will be the top pick.

“If the Knicks are No. 1, even if you like RJ better, you have to draft [Zion] or the fans will overrun you,” Pastner told The Post on Sunday after being honored by the Jewish Heritage Sports Association in a ceremony at Temple Israel in Lawrence, Long Island. “There are some NBA teams I know who like RJ more. They would rather be the No. 2 pick.

“Either one you’re getting a potential All-Star. But Zion’s marketing/season tickets, you can’t turn it down. The former president of the U.S. [Barack Obama] and LeBron [James] weren’t going to the game watching Duke. They were watching Zion.”

Pastner will start his third season at Georgia Tech after seven seasons as head coach at Memphis, where he succeeded John Calipari. Pastner was Calipari’s assistant.

“You’re going to pick Zion because of the fanfare,” Pastner said. “But I’ll tell you, Barrett should be in consideration for the No. 1 pick. Whoever gets two is in a good spot.”

That’s good news for the Knicks if they don’t win the May 14 lottery. The Knicks have a 14 percent shot at No. 1 and 13.4 percent shot at 2.

It is not that Pastner isn’t a “Zionist,” he just thinks Williamson and Barrett are the clear-cut top two players in the draft — with Murray State point guard Ja Morant a distant third.

Unlike Barrett/Williamson, Pastner said Morant didn’t play “in the best league in the world outside the NBA,” referring to the ACC.

“Morant is very good, his statistics are incredible,” Pastner said. “But RJ and Zion produced every night against the level of players, against the athleticism, you’ll see in the NBA.’’

Against Georgia Tech in January, Williamson notched 22 points in Duke’s 66-53 victory.

“I thought his quickness off the floor and physicality is incredible,” Pastner said. “Our center, James Banks, first-team All-ACC, a couple of times [Zion] got the ball at the elbow and just got by Banks like he wasn’t even there. It wasn’t that Banks wasn’t strong. It was Zion. Coaching against him, I felt like he was an NFL middle linebacker playing college basketball.”

Pastner said an NFL team should have taken Williamson as a flier with one of the last picks in the draft.

“When I first got the job at Georgia Tech, I went to see him in AAU,” Pastner said. “On the warm-up line, he looked more like a football player. Then he plays and it’s, ‘Wow.’ His feet are so quick considering the size of his body. It’s something God gave him with his body — how it moves with power, grace. It’s a one-time talent athletically.”

However, Williamson still has to develop his “skill set,” Pastner said. Scouts have questioned Williamson’s 3-point and free-throw shooting.

“Everyone’s comparing him to LeBron — he’s not there,” Pastner said. “Give the guy a break. He cleaned up, won the awards and you look at his stats, he produced. So he’s going to be a good pro. Whether he ever gets to the status of LeBron, let him score a point or two in the NBA.

“But he has that trajectory. He’s going to be a double-double guy in the NBA because of his athleticism. That doesn’t mean he’ll be one of the top 50 who ever plays.”

Pastner said he saw a lot of Barrett in high school. Barrett and Georgia Tech guard Michael Devoe attended Montverde (Fla.) Academy together. Against Georgia Tech, Barrett scored 24 points with 11 rebounds.

“One thing RJ can do is flat-out score the ball,” Pastner said. “In scoring, you either can or can’t. He just has an innate ability to put the ball in the basket.”

The Jewish Sports Heritage Association also honored Marty Riger, director of the Knicks kids summer basketball camps for 28 years and also longtime U.S. coach in the Maccabiah Games.