Gonzalez even attended Doncic’s youth camps. After one, he saw the teenage wunderkind outside the gym, and his mother encouraged him to ask for a picture. That photo of a young Doncic with an even younger Gonzalez has sprouted up on social media feeds this season.

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Still, Gonzalez knew there was no time to be starstruck when stepping into the Celtics/Lakers rivalry Sunday, with luminaries such as Magic Johnson and Kareem Abdul-Jabbar in the crowd.

Less than 30 seconds after Gonzalez entered with 4:40 left in the opening quarter, Doncic appeared eager to test him. Gonzalez fought through a screen from Lakers forward Jaxson Hayes, but as he chased Doncic his momentum carried him just far enough past him for Doncic to calmly step back and fire up a 3-pointer that swished through the net.

As the two ran back downcourt, Doncic smiled and had words about the rookie seminar he was conducting in real time.

“He asked me if I liked [the shot],” Gonzalez recalled later. “I said, ‘Yeah, sure.’ ”

Doncic kept testing Gonzalez, but the rookie was undeterred. A minute later, Doncic’s fadeaway in the paint rolled off the rim. A minute after that, Gonzalez stayed focused amid a series of fakes and leans from Doncic and eventually forced a contested baseline jump shot that thudded off the back rim and went out of bounds off the Lakers.

Gonzalez jogged to the other end and pointed his finger in that direction, indicating that it was now Boston’s ball.

When asked about those two stops later, though, he mostly shrugged.

“You can wish for him to miss, but you can’t really stop him,” he said. “He’s one of the most, if not the most talented player in the world, and he’s an offensive machine. So, you’ve got to stay in front of him as best you can. But it’s really, really difficult.”

In all, Gonzalez guarded Doncic for 10.5 possessions, and the Lakers star drew one shooting foul and scored 7 points. Gonzalez said that guarding Doncic creates so many challenges, because his vast collection of moves makes it impossible to predict what is coming next.

Still, Gonzalez left an impression on Doncic. After the Celtics’ 111-89 romp, the Lakers guard called Gonzalez a “special” and “amazing” young player.

“We all know he’s a very high-effort player,” Doncic said. “He’s all around the court. It’s only his first year. He’ll have time to learn. But I think he’s going to be a very important piece for every team he plays for.”

Gonzalez, who shared a hug with Doncic when the game ended, relished his first NBA matchup against him and hopes he added some intelligence that will help him in the next one. But he also took a moment to appreciate the opportunity to face his childhood hero.

“It’s a dream come true,” he said. “I’ve been one of those kids who entered the Real Madrid academy at 11 years old, and I had him as a reference and a player I’d like to be in the future. So, of course it’s amazing to see his success, and be the player and the person he is.”

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.