An extremely important zwischenzug, which wins for White.
It was not too late to step on a hidden mine with 27.Bg5? g6!. Here, it is Black who plays the zwischenzug, after which he is simply better.

28...Qe5 29.Bd3+–.

Black must part with material.

Black resigned.

The only move to maintain equality was the zwischenzug 28...e2!. A draw is achieved after 29.Re1 (29.Rd7+?! Qxd7! (not 29...Kf8? 30.bxc7 e1=Q+ 31.Bf1 Re8 32.Rf4! Bxf4 33.Qxf4 Qe6 34.Rd8 Kg7 35.c8=Q Qxc8 36.Rxc8 Rxc8 37.Bd3+–; 29...Nxd7 30.Qf7+ Kd6 31.Qd5+ Ke7 32.Qf7+=) 30.Qxe5+ Kf8 31.Qxb8+ Ne8 32.Bxe2 Qxa4 33.b7 Qb4 34.Bh5 Re6 35.Kh2 Re7 36.Bf3³) 29...Rxb6 30.Rxe2 Nd7 31.Rd2 (31.Qf7+ Kd8 (31...Kd6 32.b4!!+–) 32.Ra8+ Rb8 33.Rd2 Bd4 34.Re2 Be5=) 31...Bd4 32.Re2+ Be5 33.Qf7+ Kd8 34.Ra8+ Rb8 35.Rd2 Bd4 36.Re2=. The two sides cannot avoid a repetition of moves.

A gift of fate.
White misses the simple win 29.Ra7! Qxa7 30.Qxe5+ Kf8 31.Rd8+ Kg7 32.Rg8+ Kh6 33.Qf4+ Kh5 34.Be2++–.

White resigned.

White has the advantage, but the tactical solution is rather unusual.

Lightning from a clear sky.
More complicated but possible was 17.Qxa7!? Nc6 18.Qa8+ Nb8 19.a4! Bd6 20.a5 Qc6 (20...Bxg3 21.a6 c6 22.Bf5+–) 21.Bh4! Ne4 22.Bxd8 Rxd8 23.a6 b6 24.Qxc6 Nxc6 25.Bxe4 dxe4 26.Rxe4, with the advantage in the endgame; But nothing was achieved by 17.Bb5 c6 18.Qxa7 cxb5∞.

Losing at once. But even after the strongest continuation, White keeps extra material:
A) 18...Qd7 19.Qxa7 Qd6 (19...Qe8 20.Rae1 Ne4 21.Qa8+ Kd7 22.Qxb7 Nd6 23.Qxd5+–) 20.Rae1 Bf8 (20...Qa6 21.Qxa6 bxa6 22.Rxe7+–) 21.Rf5 Qc6 22.Bh4 Bg7 23.Re7 b6 24.Bxf6 Rde8 25.h4±;
B) 18...Qg6 19.Rxe7 Rd7 20.Rxd7 Nxd7 21.Qxa7±.