There wasn't anything to dispute here. With a little under nine minutes remaining in the fourth quarter and the Spurs leading 88-66, Bonner attempted to set a high screen to free Patty Mills from Smart's on-ball defense. After fighting through an Aron Baynes screen, Smart appeared to wind up and deliver a right-handed, close-fisted blow to Bonner's groin. San Antonio's veteran forward staggered backwards and immediately took issue with Smart, going chest-to-chest with Boston's rookie guard before the referees intervened.
Although no foul was called initially, the referees convened and assessed a flagrant foul 2 to Smart, a designation that refers to contact that is deemed "unnecessary and excessive" and which requires an automatic ejection. Smart departed with 10 points and four assists in 23 minutes.
The NBA league office will review the foul, as it does all flagrant fouls, to determine whether an additional fine and/or suspension is warranted. The Celtics' next game will be in Boston against the Pistons on Sunday.
Kawhi Leonard led the Spurs with a game-high 22 points, seven rebounds and three steals. Tiago Splitter added 18 points and six rebounds in the win.
San Antonio improved to 43-25. Boston fell to 30-38.