LAS VEGAS — Mikel Brown Jr. had to wait a while for his pro debut. Nets fans had to wait far longer for a prospect like him.

Brown’s first appearance in a Nets uniform was worth the wait.

Their highest-drafted player since 2010, Brown sat through their first two games of summer league. But when he finally took the court in the California Classic Finale, he looked the part of the No. 6 pick — and a big building block.

“Very, very — not even anxious — I was just fuming,” Brown said of his pro debut in Monday’s 100-79 rout of Golden State. “I was kind of like a fire, a fire being lit. I was just ready to hoop, man. It was more of that.