Despite enjoying most of the possession, the African champions struggled to break down a stubborn Iranian defence, and Okocha believes that most of the blame should be placed at Keshi's door.
"We were poor but we hope to get better as the tournament progresses," the 40-year-old told BBC Sport.
"This was a must-win for Nigeria but we did not take it. We did not do enough in terms of our tactical play. Keshi did not do enough work on the team.
"The tactical play of Eagles was so bad, I hold Keshi responsible for this."
Nigeria take on Bosnia and Herzegovina in their second Group F fixture on Saturday night.