The incident occurred midway through the fourth quarter after Cuban had been interacting with the fans in the section behind the Mavericks' bench. Cuban was not injured.
"I don't know what it was, but something hit me in the face," said Cuban, who encouraged fans to boo him more by putting his hand by his ear.
Extra security was assigned to the area behind the Mavericks' bench for the remainder of the game. There were no other issues.
Tim MacMahon covers the Mavericks for ESPNDallas.com. Ben Rogers of ESPN 103.3 contributed to this report.