He should not allow Black to open lines for his rooks; instead, he should prefer 20.bxa5 bxa5 21.Nd4, with chances of equalising.

More active is 22.Nc3, after which Black’s advantage is minimal.

The pawn stands slightly more actively, taking c4 from the white knight, and opening a path to b6 for the bishop.

It was useful to make luft.

Losing at once. He could resist further with 33.h3! Qa3 34.Bc3.

White resigned.

The knight jump into d3 is natural and strong – Black gets the two bishops and active piece play. But in view of the fact that White will have to part with his light-squared bishop, Black first provokes a weakness:

If 17.bxc5 Bxa1 18.cxd6 Qxd6 19.Nxb7 Qe7 20.Nc5 Rb8 21.Nb3 Qf6 22.Kf2 Bc3 23.Qc2 0-0, White does not get full compensation for the exchange.

Better was 22.bxc5, strengthening the position in the centre. However, because of the weakness of the kingside light squares, the advantage would still lie with Black.

With such a bishop, White has to surrender a rook, and the rest is a matter of technique.