White resigned.

Because of the back-rank mate, the queen is immune, and her sudden inclusion in the attack immediately decides the outcome of the game.

22...Qb6 23.Qxh7 Rf8 24.Rb3+–.

23...Rf8 24.Nxd4+–.

In the game, White missed this chance, and after 22.Rd3 Bxh4 23.Nxh4 Rxb5 24.axb5 Ne5, Black had the initiative and went on to win.

Black does not threaten any dangerous checks and, more importantly, has no mating threats. Meanwhile, his bishop and central pawn are hanging, and the former cannot move away. It seems time to resign, and the only question is whether he can pose a threat, given that the entire white army has advanced a long way forward, leaving his king unprotected. And there is indeed such a possibility – moreover, it lies on the surface:

In the game, there occurred 30...Bxg5 31.Qxg5 Kg7 32.Rf5 exf3 33.Qg3 with a draw on move 40.

No better was 31.Kf2 Qc8 32.Bxe4 Qh3.

The queen comes into the attack with decisive effect.