Spain and Norway traded blows in a thriller that ended 28-27 at Yoyogi National Gymnasium in Tokyo on Monday.
Both nations entered with tournament-opening wins under their belts and the result was in the balance until the final whistle in Japan.
Adrian Figueras Trejo scored 10 times in one-upping Norwegian leading scorer Magnus Jondal, who was a constant presence on the floor.
Spain trailed 14-13 at the break but rallied to France as 2-0 teams in Group A. France beat Brazil 34-29, while Germany clipped Argentina 33-25.
Earlier, Denmark became Group B's first 2-0 team when it beat Egypt 32-27. Sweden joined them with a surprisingly difficult 28-26 win over Japan. Bahrain dropped its second straight one-point game, losing 26-25 to Portugal.