Japan flunked its first test at the Confederations Cup as Alberto Zaccheroni's side went down 3-0 to two-time defending champion Brazil in the opening match on Saturday.
A cracking third-minute strike by Neymar and second-half goals from Paulinho and Jo easily handed the three points to Luiz Felipe Scolari's side, which will face Mexico on Wednesday. Japan plays Italy next at Recife the same day.
Manchester United's Shinji Kagawa tipped his hat to Neymar for the goal, but said Japan did not help itself with a lackluster performance littered with mistakes.