The west Africans were left heartbroken after Saturday's loss moved them to the bottom of their group standings
Nigeria 'have to do it the hard way' to qualify from Group D, according to Garba Lawal.
An own goal from Oghenekaro Etebo and Luka Modric's penalty condemned Gernot Rohr's men to 2-0 defeat in their World Cup opener against Croatia on Saturday.
The result left them at the bottom of their group, with games against Iceland and Argentina - both of whom are tied on one point after they played out a 1-1 draw - still to come.