Doncic was ejected for the incident, which occurred with 3:00 remaining in the third quarter of the Mavericks' 111-99 loss to the Indiana Pacers. The gesture earned the rookie his second technical foul and an automatic ejection.
After the game, Doncic said he "was just trying to play soccer" and juggle the ball with his feet.
"I wasn't playing well,'' he said. "For sure, it was one of the worst games I've played this season, so yes, I was frustrated. I didn't know I would be ejected because there are different rules in Europe."
Doncic played for Real Madrid of the EuroLeague for four seasons before being selected as a 19-year-old in the 2018 draft.