8.Nd4 Rc3 intending ...Nd5.

Heading for b8 in order to attack the weakness at b3.

. After this exchange White won't be able to cover both weaknesses at b3 and f4.

2.Rxc1 Qxc1+ White loses the f4-pawn.

Eradicating the blockade of the passed pawn.

On other moves 4...d3 is decisive.

The pawn reaches d2 with decisive effect.

Ruling out any mating ideas with 13 Ng6. White resigned.

Heading for d3 to block the passed pawn.

White exploits the exposed position of the bishop on a6 in order to create some activity.