The knight heads for d4, but this does not bring great benefits, since the other black pieces are uncoordinated, especially his rooks.
It was stronger to open up the bishop with 14...e4, or stop the white pawn by 14...Nd7.

Thanks to the knights, a mating net is forming around the black king.

Black has no moves to strengthen his position, so White permits himself some prophylaxis – the king moves away from the knight check.

Black resigned.

Black threatens perpetual check, so White must seek a way to advance his pawn with tempo.

Promoting to a queen is no good, so we promote to a knight! The white forces are sufficient to cope with the lone black queen.

Both sides’ passed pawns are very far advanced, and each is a potential queen. Therefore, to gain a tempo, Black sacrifices a rook:

The armada of black pawns marches unstoppably to the promotion squares.

58.a7 d2 59.Rg1 c2 60.Rb8 c1=Q 61.a8=Q Qxg1+ 62.Kxg1 d1=Q+ 63.Kg2 Rc2+–+.