The Cleveland Cavaliers started to lose control at the end of their Game 2 loss to the Boston Celtics in the Eastern Conference finals. Down by eight points with just under four minutes remaining, the Cavaliers needed a stop. Instead, they unraveled. As Marcus Smart and Al Horford ran a pick-and-roll, Horford rolled to the rim looking for the lob from Smart. 

As he was in midair, on his way to an alley-oop slam, J.R. Smith shoved Horford in the back, sending him crashing to the ground. It was a very dangerous play, and Smith was hit with a Flagrant 1 foul. In addition, Smith and Marcus Smart were each given a technical foul after Smart confronted the Cavs guard for the dirty play. 

The flagrant gave Horford two shots and the Celtics the ball back. Horford hit both of the free throws, then on the ensuing possession went reverse for a bucket that pushed the Celtics' lead up to 12. 

That sequence essentially ended the Cavs' hopes of a comeback. In the end, the Celtics won by 13 -- 104-97 -- to take a surprising 2-0 series lead. 

After the game, Smart said Smith's play was a "dirty shot" and added that it wasn't the first time Smith has done something like that. 

Smith, for his part, said it was the right call to give him a flagrant.