They were beaten by two goals to one in Florida by the United States who have imposed themselves on a brace by the Sunderland striker Jozy Altidore (32, 69). The penalty of Liverpool midfielder Victor Moses (86) wa not enough for Nigeria to restore parity.
The Americans have won all their warm-up matches: Azerbaijan (2-0) and Turkey (2-1).
In Group G, they will face Ghana, June 16, in their opener and then Germany and Portugal.
Nigeria who are housed in Group F will play their first match against Iran on June 16 before playing Argentina and then Bosnia.
During their preparation, Nigeria have tied two draws against Scotland (2-2) and Greece (0-0).