Donovan Mitchell and Grant Williams were trading blows – via Twitter.

Mitchell posted pictures of his workouts at the Cavaliers practice facility on his Twitter account, but one particular photo of him bench pressing using a chest pad caught the attention of new Dallas forward Grant Williams.

Williams, traded to the Mavericks from the Celtics this week, saw the post and commented “Chestpad brother…how old are we.”

Mitchell then replied with a shoulder shrug emoji accompanied by a picture from a game in March where the Celtics and Cavaliers played against one another – a moment in which Williams was going to the free throw line with the game tied at 109 with 0.8 seconds left.

Williams told Mitchell he was going to make both free throws, ultimately missing both before the Celtics lost in overtime.

Williams has never lacked confidence – he confronted Jimmy Butler during this past year’s Eastern Conference Finals after hitting a three pointer to give Boston a lead in the fourth quarter of Game 2.

That also did not work out well for the forward, as Butler scored nine of his 27 points after that interaction.

Dallas Mavericks fans should no doubt be excited that they are adding Williams, a prototypical 3-and-D player who can guard multiple positions and can shoot the three at a 40 percent clip, to their roster to space the floor for guard Luka Doncic.

But if Williams starts talking with an opposing star player in a crucial moment, don’t be surprised if the Mavs ends up blowing that game down the stretch.