When one pawn is still on its sixth rank, only real threat is more advanced pawn and the winning area is much bigger. With central pawns win can be easily achieved by bringing the queen between pawns (e2) or in front of the more advanced pawn (d1), but equally good is to establish double control of these squares with the help of his king. Thus in cases of Kb1, Kb2 or Kb3 immediately decides 1.Kc2.
