Kevin Garnett is one of the NBA's fiercest competitors, which sometimes results in him exchanging words with opposing players. Things got a bit more heated than usual at the conclusion of Sunday's season opener, though.

Garnett was unable to sink the final shot, which allowed the Knicks to hold on for a 106-104 victory in what was a very intense, back-and-forth battle at Madison Square Garden. Upon the miss and the sound of the final buzzer, Garnett got into it with former teammate Bill Walker. Walker, of course, played 29 games with Boston in 2008-09 and eight games with the C's in 2009-10 before he was shipped to the Knicks as part of the deal that put Nate Robinson in green that season.

Garnett and Walker exchanged words, which culminated with Garnett grabbing Walker by the throat and shoving him away. The two were then restrained by other players, including the Knicks' Baron Davis, who is sidelined with a herniated disc in his back.

After the game, Garnett brushed the incident off when asked about it by reporters. We'll see if the league elects to do the same, or whether some sort of discipline will be handed down.

Either way, don't be surprised if these two Atlantic Division teams exchange pleasantries again this season, as the Celtics-Knicks rivalry seems to be back in full swing.

Check out Sunday's altercation in the video below.