Draymond Green has a message for Mavs rookie Dennis Smith Jr.

When an NBA rookie decides to challenge a veteran like Golden State Warriors All-Star forward Draymond Green at the rim, things probably won’t go down too well.

But on Monday night in the Warriors game against the Dallas Mavericks at American Airlines Center, Dallas Mavericks rookie Dennis Smith Jr. went straight after Green, attempting to dunk on him late in the third quarter.

Things went as you may have expected. Smith missed the dunk. Green fouled him. The two exchanged words, with Green’s being the most pointed.

“You’ll never dunk on me,” said Green, taunting Smith.

Green addressed Smith’s dunk attempt after the game, telling reporters: “Yeah that s*** ain’t happening … this ain’t summer league bro … better luck next time.

“It ain’t happening. C’mon dude.”

When asked if Green knew about Smith coming into the game, Green replied as only Green would.

“I got Instagram, just like you got it. So I’ve seen him on Instagram.”

Smith also got a chance to address the back-and-forth exchange after the game, telling reporters: “I don’t know what he (Green) was talking about. You can’t say nothing if you foul me.”

You have to credit to Smith though, during the on court exchange he smiled the whole way through. He’ll get his moment to posterize another player another time — just maybe not Green.

The Warriors beat the Mavericks Monday night, 133-103. Green had 10 points, eight assists and seven rebounds. Smith finished with 10 points and six rebounds.