The African nation takes on the Group F minnows in their curtain raiser in Brazil on Monday, and are expected to dispatch of their opponents despite their underwhelming lead-in.
Nigeria twice came from behind to draw with Scotland 2-2, were well held by Greece 0-0 and lost to the United States 2-1 in their warm-up friendlies.
But Keshi said he was not bothered by the scorelines in their recent matches.
"We are in Brazil for serious business," Keshi said.
"Friendlies are meant to serve as rehearsals; the team is different from competitive matches.
"This is not an excuse for our performance in the matches, but seriously speaking, the results do not mean anything to me, evaluate us in the World Cup."
Keshi said Argentine superstar Lionel Messi was not on their agenda until they had negotiated group games with Iran and Bosnia-Herzegovina.
"We have two games before thinking about Messi," he said.
"We will try to do better than we did in 2010 in South Africa but we'll see what happens when the World Cup starts."
Nigeria have not escaped the group stage at a World Cup since they topped their pool at France 1998, going winless in South Korea/Japan in 2002 and South Africa '10.