The Spurs arranged the second act as a show of support following a run of disparaging tweets about Latinos and immigrants during De La Cruz's nationally televised performance before Game 3 on Tuesday.
De La Cruz, who was born and raised in San Antonio, said he was grateful and excited for being invited back.
"It makes me feel real good about myself," De La Cruz said. "It makes me feel like, in San Antonio, I know there are a lot of people that encourage me to keep on doing what I want to do."
Before the game, Popovich bemoaned the "idiots" who posted bigoted comments.
"He's a class act," Popovich said. "Way more mature than most his age. And as much as those comments by the idiots saddens you about your country, he makes you feel the future could be very bright."
Other celebrities and politicians also rallied behind De La Cruz. They included San Antonio Mayor Julian Castro and actress Eva Longoria, formerly married to Spurs star Tony Parker.
Castro, the keynote speaker at last year's Democratic National Convention, introduced the boy Thursday night and gave him an official proclamation from the city.
"The message is that no matter what someone's background is, we have so many Americans who have true talent," Castro said. "And Sebastien is one of them."