The Nigerian U-23 team, Dream Team IV opened their campaign with a 5-4 victory over the Japan U-23 team.
Sadiq Umar opened the goalscoring record with a lovely goal at the 6th minute while Oghenekaro Etebo tripled it before half time.
Etebo scored two more goals in the second half to make the scoreline 5 against the 4 of Japan.
On scoresheet for Japan are: Kokori, Minamino, Asano and Suzuki.
Nigeria will play Sweden and Columbia in other Group B matches of the 2016 Olympics.