Oklahoma City, OK – James Harden had 13 points, seven 83 victory over the Dallas Mavericks.
Russell Westbrook added 12 points and Kevin Durant contributed 10 for the Thunder, who host Orlando on Sunday to open the regular season.
Jerome Randle scored a game-high 17 points, while Brandan Wright had 12 and Shawn Marion dropped in 10 in a losing effort.
Dirk Nowitzki had six points on 2-of-10 shooting for the defending champions. Dallas hosts Miami on Sunday in a rematch of last season's finals to start its season.