Sweden's World Cup spy Thomas Lyth, who has been following Nigeria's every move for the last six months, has said he is impressed by the Super Eagles' team spirit.
However, he also thinks he may have helped work out how to beat them.
Lyth was at the African Nations Cup in Mali, and also watched Nigeria's warm-up matches and has been at all their open training sessions.
He has even watched the players off the pitch.
He even went to a reception held for the team by the people of Hiratsuka, where the Nigerians had their training camp, to see if he could glean any information.
"I am searching for any little sign, looking to see if the players look confident and united, or whether there might be some problems," Lyth said.
"I might be able to tell if a player has a slight injury, or is someone looks a bit unhappy."
Information
Lyth makes regular reports back to the Swedish coaches Tommy Soderberg and Lars Lagerback, and says he has told them that the Super Eagles have come a long way since they were knocked out of Mali 2002 in the semi-finals by Senegal.
"They have more speed and better teamwork, in both offence and defence, and they are playing well with each other," Lyth said.
"They work around the player with the ball, which shows that the players are all good pals".
Lyth says every bit of information will be a help if they are going to defeat the Nigerians.
"We have our ideas about how to beat them," he stated.
"But we know it is going to be difficult. They play a lot of man to man marking, which could be one way of breaking them down."
Counter-productive
For their part, the Nigerians are taking the opposite approach, with coach Adegboye Onigbinde dismissing the use of spies.
"I don't believe in studying other teams," Onigbinde said.
"What is the point of filling my head with that? Let them do what they want."
"Spying can be counter-productive. The spies from Argentina saw us against Paraguay, but were we the same against Scotland or Ireland?
"We have played with different boys in each game. So what did they learn?"
And the idea of instructing players to adopt a particular style against different teams is definitely out.
"Players should not be robots. They should not be in straitjackets. Once on the pitch they know what they have to do and I leave them to get on with it."