Former Denver Nuggets head coach George Karl is no stranger to criticism, or to Twitter, as the 72-year-old can often be seen offering his thoughts on the popular social media app.

His latest being incendiary comments directed towards former NBA guard J.R. Smith, a player whose talent was only matched by his immaturity for well-documented segments of his career. Now largely matured, the 37-year-old Smith is a student at North Carolina A&T State University, where he plays for their golf team.

Making an appearance on former NBA guard J.J. Redick's highly regarded podcast, The Old Man & the 3, Smith claims that Karl's inability to draw up suitable Out-Of-Bounds plays was the reason the Nuggets lost to the Los Angeles Lakers in the 2009 Western Conference Finals.

“Seriously,” Smith begins, before laying into the 2013 Coach of the Year. “We didn't have one out of bounds play my whole time playing for this man. If you go back to that Lakers series [in 2009], we lose on three out of bounds plays.”

The Nuggets lost to the Lakers in six games in the 2009 Western Conference Finals.

Smith, then in his fifth career season, averaged 12.7 points and 3.3 assists per game that series. However, he did so while shooting 38.7 percent shooting from the field and 29.8 percent from 3-point range.

Not one to take an insult laying down, Karl offered a backhanded compliment to J.R. in response.

On the one hand, he says he's happy to see what Smith is currently doing in life. He also says that the two-time NBA champion is the second-best athlete he's ever coached.

As far as his play-calling is concerned though?

“I'm sure JR was smoking weed when we practiced them but it's 15 years ago so let's just celebrate and move forward!”

Ouch.