LeBron James' foot injury didn't stop him from going to Bronny's playoff game on Thursday night ... and he's sure as hell glad that was the case, 'cause he got to see his kid go OFF in a thriller!!
The young James and his Sierra Canyon squad went up against sixth-seeded Etiwanda in Chatsworth, Calif. in a CIF State regional quarterfinal game ... and Bronny had quite the night.
The 6-foot-3 guard -- who was just selected to the McDonald's All-American Game -- scored 21 points from all over the court .