Originally posted by paultopia
Can black hold after giving some material back with 21. ... Rf5? If 22. Bxf5 exf5 the attack ends, and 22. Qh3+ Bh4 23. Nxh4 (not Qxh4, where the attack ends again) Kg1 and it looks like the king has an escape square. Black's still hurting in that line, and the endgame doesn't look good, but it at least avoids the mating net...
Still leads to mate.Long variation but not overly difficult to find because,after 23...,Kg8,all moves are forced:
21...,Rf5 22.Qh3+,Bh4 23.Nxh4,Kg8? 24.Nxf5,exf5 25.Qh7+,Kf8 26.Qh8+,Ke7 27.Qxg7+,Ke6 28.Qf7+,Kxe5 29.Qxf5,Kd6 30.Ne4+,Kc6 31.Qc5,Kd7 32.Qd5+,Kc8 33.Bf5+,Qd7 34.Qxd7+,Kb8 35.Qd8#
23....Rh5 might stop the mate(further clogs up the h-file) but costs so much material there's no point in prolonging the struggle any further.