A brilliant queen sacrifice.

For the queen, White has rook, bishop and two pawns, but Black’s biggest problem is the weakness of g7. The attack is unstoppable.

Black resigned.

White blocks the f-pawn from moving.

But not 25.gxh3 Qc5+ 26.Kh1 Qc6+ 27.Kg1 Qc5+=.

On 25...Qc4+, White wins with 26.Ke1 (or 26.Ne2+–).

Not 26.Ke1 Qe5+, and Black wins.
Black resigned. There could follow 26...Bxe2+ 27.Ke1 (of course, not 27.Kxe2 Rfe8+ 28.Kf3 Qc6+ 29.Kg4 Qxg2+–+) 27...Qa5+ 28.b4, with inevitable mate.

Black’s hopes are exclusively tied up with advancing the f-pawn. The following typical blockading sacrifice prevents this.

Black has no way of meeting the white attack, and so he resigned.