Finding the only path to victory

Leonidov – Jiganchine, 1997 (variation from the game)
 Black to move

If you guessed the first few moves correctly, then there is another sequence of “only moves” that needs to be found:
Black to move
There are plenty of candidate moves to consider – …Rf2, Bxh3, Ng3, Nf4, etc, but only one leads to the win. Can you find it?
Interestingly, when I made a video about this game – I had thought that Black only has a draw here.