? Ne6 would have been better, as this wins the g5 pawn by force
26. Nd1b2 Rh8d8
However Black now notices that White's King does not have g2 or e2 as flight squares, as these are covered by the Knight, therefore has 'back rank weaknesses'
27. Rg3g4 Kd7e6
The King clears the path for the Rook... White must play something like f2-f3 to enable an escape route for the King
28. Rg4h4
Black can ignore the threat to h7
28... Be7a3
This hits the only defender of d1, the square that is needed to give checkmate... White must lose a piece, or perhaps just an exchange with Rxf4