Cooper Flagg put the league on notice before he ever played an NBA game

SEVENTEEN-YEAR-OLD COOPER FLAGG had not yet played a single game for Duke when he walked into UNLV's Mendenhall Center on the afternoon of July 8, 2024.

But he piqued the curiosity of the future Hall of Famers preparing for the trip to Paris to play for Team USA in the 2024 Olympics.

Flagg had been the most hyped and anticipated American high school prospect since LeBron James, who was the No. 1 pick in the NBA draft more than three years before Flagg was born. James and the rest of Team USA were quite familiar with Flagg's name, if not yet his game.

It had been more than a decade since an amateur had been invited to play for the Team USA select squad. Doug McDermott and Marcus Smart were accomplished collegians when they received the call in 2013.

This scrimmage at Team USA's training camp would be the biggest test yet for the teenage phenom. Would Flagg be intimidated facing perennial All-Stars he grew up watching on TV? Would he be jittery playing in a small gym with NBA coaches and executives surrounding the court?

The answer: absolutely not.

"Zero nerves," 10-time All-Star Anthony Davis told ESPN, recalling his first impression of the 6-foot-9 forward who will start alongside him this season in the Dallas Mavericks' frontcourt. "He went out and balled."

Flagg is back in Las Vegas for one last tune-up entering his rookie season, as the Mavericks play the Los Angeles Lakers in their preseason finale Wednesday night at T-Mobile Arena. But Flagg's welcome-to-the-NBA moment occurred 15 months ago about 2½ miles away, when he made it clear he could make an immediate impact in the league, although he'd have to wait a season to become draft-eligible.

Flagg was already the consensus favorite to be the No. 1 pick in the 2025 draft when he arrived at the Team USA training camp in Vegas. If there was any doubt that he'd go No. 1 in the draft, it was eliminated by the end of the scrimmage, when the Olympic squad survived a Flagg-fueled comeback to squeak out a 74-73 win.

It only amplified the anticipation for Flagg as he headed to Duke, where he again more than met expectations, earning national player of the year honors while leading the Blue Devils in every major statistical category en route to an ACC title and a Final Four appearance.

Now, after the veteran-laden Mavs stunningly cashed in 1.8% lottery odds to land Flagg with the No. 1 pick, the expectation is that Flagg can expand his game as a rookie while proving himself as the rare teenager ready to affect winning right away in the NBA.

"I don't know if it was about proving anything to myself or just feeling comfortable and getting confidence from that experience," Flagg told ESPN. "I definitely just had that feeling that I knew I belonged. I knew I could be out there."

WHILE STUDYING TAPE of Flagg doing everything at Duke, Mavs coach Jason Kidd wondered if Flagg could do even more.

Kidd saw shades of another former Duke star in Flagg's game: Grant Hill, who shared the Rookie of the Year award with Kidd in 1994-95, when the 6-foot-8 Hill ran the point a lot for the Detroit Pistons. Kidd saw the same phenomenal blend of feel and force in Flagg that Hill had coming out of Duke.

"I saw that, too," Hill, who as managing director of Team USA invited Flagg to join the program's select team and called some of his college games for CBS, told ESPN. "He tries to play the complete game. You look up and he's got 22 points and it doesn't even feel like he looked to score. He's so unselfish. He defends. He just tries to do what's necessary to win games."

When Flagg arrived in Dallas, Kidd was determined to find out how he could handle point guard responsibilities. Kidd also wanted to see how Flagg would handle an unfamiliar role. That experiment started during his brief stint in the Las Vegas Summer League, which had mixed results as the Mavs split the two games that Flagg played at the Thomas & Mack Center.

Flagg shot poorly in the summer opener, going 5-of-21 from the field, but found his way to put his fingerprints on the defining sequence of the win over the Lakers. With a little more than a minute remaining, Flagg swooped in from the weak side to swat a layup attempt, pushed the ball in transition, drew three defenders in the paint and dished to a teammate for an open 3-pointer that gave Dallas the lead for good.

Flagg scored 31 points in 31 minutes in the second game, a loss to the San Antonio Spurs. The Mavs had seen enough -- especially pleased with how Flagg handled pressure while bringing the ball up the court -- and shut him down for the rest of summer league.

"He handled the situation as well as an 18-year-old could handle it," said Kidd, who started Flagg at point guard in a jumbo-sized lineup in Monday's preseason win over the Utah Jazz. "He has a talent about winning. It is in his DNA, and so it would be unfair not to make him uncomfortable."

THE MOST MEMORABLE moments of Flagg's time at the national team's training camp, according to Orlando Magic coach Jamahl Mosley, who was in charge of the Team USA select squad, didn't occur during the scrimmage. They happened during the few practices and meetings the select squad held beforehand.

Flagg's inquisitiveness and intelligence impressed Mosley, who especially enjoyed an in-depth dialogue between Flagg and Magic guard Jalen Suggs about the intricacies of NBA defense.

"He asked a lot of questions," Mosley told ESPN. "I think it's huge for a young guy in this situation to be able to ask the right questions. He just wanted to understand what it looks like at the next level. He's a communicator, and that said a lot to me about him. Guys like that with high basketball IQs that want to play the right way will ask questions."

Then Flagg delivered a fearless performance in the scrimmage.

"He wasn't afraid of the moment and who he was going against," Mosley said. "He was himself. I think he walked in with the quiet confidence, but then when he got on the court with those guys, that demeanor didn't change any at all."

If there is such a thing as a signature stretch during a scrimmage, Flagg put one together with a late scoring flurry as the select team rallied from a double-digit deficit. He hit a baseline turnaround from the left block over Jrue Holiday. He rose up from the right wing to drill an off-dribble 3 in Davis' face. And Flagg flew in for an and-1 tip-in over Bam Adebayo, eliciting a roar from the entire select team bench.

Those three buckets came against a trio of defenders with a combined 16 All-Defensive team selections. Flagg didn't celebrate any of them, maintaining a quiet, focused sense of calm. He called his select team stint "a big learning experience," but nothing he did against the Olympians surprised Flagg.

"He was cooking," Davis said. "He definitely stood out. Guys obviously were hearing the name, and we all knew who he was. But a lot of guys tend to, I don't want to say be hesitant, but when you're going against guys like myself, Bron, Steph [Curry], you see these guys and it's like, 'Oh s---.'

"You look up to and you idolize these guys, and now you got to go play against them. You kind of get nervous, which is normal. But for him, he has the utmost confidence in himself."

Flagg's scoring dominated the media coverage of the scrimmage, but that isn't what made the strongest impression on Steve Kerr, the former Team USA coach. Kerr was wowed by Flagg's command of the game at such a young age against elite competition.

"I just remember the force you felt," Kerr told ESPN. "You immediately felt him. And it was as a basketball player. It wasn't just like he had a huge dunk or something. No. It was the passing, the cutting, the late-clock, left-handed jump hook on the block when the offense had nothing else. It was so consistent.

"I'm coaching against him and we have the best players. He's got incredible feel. He's just huge but plays like a guard in terms of reading the game."

Kerr recalled seeing Duke coach Jon Scheyer in the gym after the scrimmage.

"I said, 'That had to make you feel good,'" Kerr said. "He just smiled."

Kidd knows the feeling.

ESPN's Anthony Slater contributed to this report.