Zion Williamson completes the alley-oop jam off a pass that first hits the backboard before the No. 1 pick dunks it down. (0:18)

METAIRIE, La. -- For a split second, New Orleans Pelicans guard Frank Jackson couldn't believe his eyes.

As the Pelicans worked on inbounds plays on the second day of training camp Wednesday, Lonzo Ball floated a pass toward the hoop that looked like it was going to hit off the backboard.

But Zion Williamson leaped up, grabbed it and threw it down, sending coach Alvin Gentry into a turnaround fist pump of excitement.

Jackson said he was shocked but, "Then you're like, 'Oh, it's Zion.'"

After a first day in which he didn't throw down any windmill dunks, Williamson made his mark with the alley-oop. But Jackson said it's something his teammates have already gotten used to.

"I've seen it," Jackson said. "It's crazy. He's an incredible athlete. That thing hit the backboard, he caught it and then he dunked it. What? C'mon man. That's not fair."

Ball admitted the pass was a little off. He said last week on The Woj Pod that he was already practicing full-court lobs with Williamson, while adding that he just needed to "put it wherever the backboard is and he'll catch it."

That played out on Wednesday.

"That wasn't the best pass, but you saw what he did with it," Ball said. "It's really hard to throw him a bad lob."

Count Pelicans forward Brandon Ingram as one of the onlookers who wasn't amazed at the end-of-practice dunk. Not because Ingram wasn't impressed, but because he's seen it from Williamson already.

"I've seen highlights," Ingram said. "I've seen pretty much everything from him, so I don't think anything more is gonna amaze me unless he just puts it between his legs twice or something."

Gentry and vice president of basketball operations David Griffin have been trying to keep expectations down for Williamson, but letting the media in for a peek at practice showed the world Williamson's dunking ability.

When asked about the dunk, Gentry said Williamson has had moments like that but so have other players.

"Nicolo Melli, I don't think he missed a shot today," Gentry said. "And there's other guys; I think Josh Gray has played well. Obviously Zion has the ability to make the ooh, aah plays, and he'll make a few of them every practice."

At the end of his interview, Jackson -- who like Williamson was a one-and-done player at Duke -- was asked if he's ever seen someone with the size and agility combo that Williamson possesses.

Jackson started to laugh while shaking his head from side to side.

"No, no, no," Jackson said. "I'll keep it that simple. He's one of one. So watch out. Just keep watching."