CHICAGO — Zion Williamson shuffled his feet, fidgeted with his hands, shifted his weight back and forth and didn’t bother to conceal his wide smile.

Basketball’s biggest sensation isn’t easily reduced to a shy 19-year-old in front of the cameras, but an unexpected meet-and-greet with former president Barack Obama did the trick. Young stars such as Williamson come to All-Star Weekend seeking validation, and the New Orleans Pelicans’ sensation found a presidential seal of approval before he even took the court for his first practice.

While Williamson was awestruck by Obama’s presence, Obama appeared thrilled to meet the top pick in the 2019 draft. The two shared an extended private conversation during a community service event on Friday, and Williamson regularly broke out in laughter as the 44th president held court. Obama congratulated Williamson on setting a career high with 32 points Thursday and reminisced about Williamson’s freshman season at Duke.

“He said I was playing great,” Williamson said afterward. “I kind of zoned out after that. That’s all I needed to hear, to be honest. I was like: ‘You’re keeping up with me? I’m 19. You probably have one of the busiest schedules in the world, and you’re able to keep up with a rookie, superstars, college people, even high school people, and tell them their stats and what they’ve been doing good, what they can work on?’ When he told me that, I just gained so much more respect for him.”

That surreal moment of arrival launched a whirlwind day that saw Williamson run the media gantlet, go through a morning practice, play video games with Chicago-area children at a Jordan Brand appearance and, finally, shake one of United Center’s baskets off its typical alignment with a rim-rattling dunk during the Rising Stars game.

“I don’t think I could tell you what time it was throughout the day,” Williamson said after scoring 14 points during Team USA’s 151-131 victory over Team World in the exhibition game that features first- and second-year players. “It was just shoot-around, event, event, media, media, arena. It was a great experience, but it went by too fast. I think I’m going to have to sit in my room later, like when I get back home, and just take in the whole day to truly enjoy it.”

Williamson represents a deep class of fresh faces at this All-Star Weekend, with 10 first-timers set to play in Sunday’s All-Star Game and three — Luka Doncic, Pascal Siakam and Trae Young — slated to start. That wave of young talent, made possible by a rash of injuries to established superstars such as Kevin Durant and Stephen Curry, is the largest for an All-Star Game in nearly 20 years.

Yet it was Williamson, the much-ballyhooed top pick in June’s draft, who stole the show before the focus finally will shift to captains LeBron James and Giannis Antetokounmpo and Sunday’s All-Star Game. More than 100 media members swarmed the court at DePaul’s Wintrust Arena for Williamson’s Friday morning news conference, and he was whisked from appearance to appearance through crowds of gawkers by a large security detail. A knee surgery in October caused him to miss the Pelicans’ first 44 games and cost him a shot at playing Sunday, but the warm and, at times, manic reception suggested he will be a fixture at the midseason showcase for the next decade.

Williamson entered the weekend with significant positive momentum. His Jan. 22 debut collected more than 2.3 million total viewers on ESPN, and he has performed like an all-star in his first 10 games, averaging 22.1 points, 7.5 rebounds and 2.2 assists while shooting 58 percent from the field.

“He’s very explosive, very talented,” TNT commentator Charles Barkley said Thursday at a media appearance at the House of Blues. “He seems like a really good kid, and hopefully he can stay healthy.”

Despite his lengthy absence and limited body of work, the NBA invited Williamson to play in the Rising Stars game and then positioned him next to Obama at the charity event, knowing his presence would bring extra attention to the festivities. The plan worked, with the Rising Stars game averaging more than 1.4 million viewers — making it the most watched since 2015 — and video clips of Williamson and Obama drawing millions of social media views.

Williamson didn’t disappoint Friday night, rising high to throw down an early alley-oop from Memphis Grizzlies guard Ja Morant, his former AAU teammate in South Carolina, and closing the night with several spectacular missed dunks in an impromptu showcase. The United Center crowd repeatedly gasped at his signature highflying heroics, and one of his first-half dunks knocked the entire hoop off-kilter. At halftime, arena workers brought out a ladder to restore the basket to its proper configuration.

“I don’t know which dunk it was on, but I don’t think it was me,” the 6-foot-6, 285-pound Williamson quipped. Of course, there were no other suspects.

Like Shaquille O’Neal before him, Williamson mixes violent athleticism and goofy charm. During an afternoon game of NBA 2K at the Jordan Brand event, Williamson found himself losing badly to a young child who was playing as the Chicago Bulls. Williamson grimaced through his defeat, telling the assembled crowd that he had just played the real Bulls and that they hadn’t provided such stiff competition.

“He’s a good human being, let’s start there,” Jordan Brand President Craig Williams said. “His personality is very open and warm. He looks you in the eye. He talks to both adults and kids alike.”

Indeed, the day’s hectic pace provided a slew of less guarded moments from Williamson, who usually comes off cautious or even scripted in his media comments. During an afternoon interview with The Washington Post, he rattled off his favorite memories of Michael Jordan and Kobe Bryant.

When it came to Jordan, the Chicago Bulls Hall of Famer whom Williamson called his “favorite player,” it was the “last shot” closing sequence of the 1998 NBA Finals against the Utah Jazz.

“He made a defensive play, got the steal off Karl Malone and iced the game,” Williamson said, careful to note the winning plays at both ends of the court.

Regarding Bryant, the Los Angeles Lakers legend who died in a helicopter crash last month, it was an oft-circulated highlight: “The play where he caught the full-court pass, wrapped it around his back and did a reverse dunk. His awareness and skill on that play were on full display.”

Williamson later revealed to reporters that his mother, Sharonda Sampson, first encouraged him to study tape of basketball stars when he was a child. Sampson recommended the holy trinity of 1980s NBA: Magic Johnson, Larry Bird and Jordan.

“When I got to Jordan, she told me to watch full games, not highlights,” Williamson said. “As a kid, the stuff he was doing was incredible to watch. Getting a steal, saving it, and then doing a backwards layup or floating through the lane, through like three people, dunking it. As a kid, that really caught my attention. From then, I just watched every full game Michael Jordan clip I could find.”

But Williamson, who has been an Internet sensation since his high school days at Spartanburg Day School in South Carolina thanks to his dunking, has studied Jordan’s slam dunk contest tapes, too. Jordan’s legendary 1988 duel with Dominique Wilkins in Chicago was another of Williamson’s favorite Jordan memories.

Although Williamson will not compete in Saturday’s slam dunk contest after missing so much time with his knee injury, he couldn’t help himself from leading a freestyle session at the end of the Rising Stars game Friday.

First, Williamson went for a 360-degree windmill that bounced so hard off the back rim that the ball caromed past midcourt. Then he threw the ball off the glass to himself and passed the ball through his legs from right to left, losing the handle just before the finish attempt. Finally, Williamson again crashed a 360, through-the-legs dunk hard off the rim.

The three misses sent Williamson retreating to the bench with a sheepish smile, but the crowd saluted the stunning attempts with cheers and hardly seemed to mind the unfulfilled outcomes. Even if he did not intended to, Williamson wound up setting a high bar of excitement for the actual event Saturday.

On Friday afternoon, a few hours before his merciless attacks on the rim at the Rising Stars game, Williamson was asked what it might take for him to enter the 2021 slam dunk contest. Doing so would generate weeks, if not months, of hype, and it would surely draw tremendous television interest.

Caught up in the highs of a day he won’t soon forget, Williamson momentarily dropped his guard and made a conditional promise that should excite fans everywhere.

“If my team’s in a good spot, I’ll be in it,” Williamson said.

Let the countdown begin.

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