Lagerback confident he can work Nigerian miracle
"I think there is a realistic chance for Nigeria to go a long way in the World Cup in South Africa," he said.
Lagerback, named as coach on February 27 but yet to take charge of a match, said he could make an impact even though he will have less than a month to prepare his squad before the finals start on June 11.
"I can make an appreciable impact with the Super Eagles despite the short time between when I took up this job and the World Cup," he added in an interview with FIFA published on the world governing body's website on Wednesday.
"I hope I will have at least three weeks to work with the players. In three weeks, you can do a lot."
Lagerback, who replaced Shaibu Amodu after January's African Nations Cup finals, will not be able to start working with his players before they finish their respective club seasons in May.
Nigeria's top footballers are drawn from leagues across Europe and the new coach said he would seek to spend time with them before the end of their domestic campaigns.
"What I would like to do now is to speak with many of the players and try to explain to them the joy and importance of playing for the team in the first place.
"I need to tell them that even if they make so much money in football playing for clubs in Europe, when it comes to the national team you must be proud of playing for your country.
"So I will try to motivate them and explain that to them as best as I can."
"But if I find out that a player doesn't want to do his best for the team, he shouldn't be in my squad," he warned.
The former Sweden coach has watched Nigeria's recent matches on video and is formulating early ideas of a potential squad.
"I believe I know much about the team already. Although it is early to say who among the players I would like to work with, the factors I would consider in picking my players are who among them are most skilful and the best of the lot.
"Nigeria have a great chance to do well in the World Cup. If you don't believe that you can win matches in a tournament as a team and as a coach, then you don't deserve to be at the tournament. Playing football at this level is all about winning.