He played for a few clubs, including Shooting Stars FC, Grasshoppers Zürich (Switzerland), Hapoel Be'er Sheva in Israel, and Chamois Niortais in France.
Opabunmi scored a goal to help Nigeria win the African U-17 Championships in 2001.
With Collins Osunwa out with injury he became Nigeria's key player at 2001 FIFA U-17 World Championship where he scored a hat-trick against Australia and won him the Silver Shoe as second highest goalscorer and also the Bronze Ball as third best player in the tournament, helping Nigeria to reach the final where they lost to France.
He attracted attention from clubs such as Manchester United, Lyon and Celta Vigo.
[5] He was a participant at the 2002 FIFA World Cup playing against England in the last group stage match becoming the 3rd youngest player to ever play in the World Cup finals after Norman Whiteside and Samuel Eto'o.