Not necessarily. If Nigeria beat Argentina, and Croatia don't beat Iceland, Nigeria would most likely top.
What happens if by next week if Argentina and Iceland both win and the goal difference is the same?
How come? Both would be 6 points with Croatia having much better GD.
What happens if Argentina win 2-0 and Iceland win 1-0?
What happens if Argentina win 2-0 and Iceland win 1-0?
What happens if Argentina win 2-0 and Iceland win 1-0?
Bottom line is, can anyone really see Argentina beating Nigeria? I can see Argentina getting thumped again to be honest.