After 31. Qf5+ , the black pieces blunder their defense playing 31. ... Kh8, and fall for a nice forced mate in 3:
1.Ng6+ Kh7
2.Nf8+ Kh8
3.Qh7#
After 31. Qf5+ , the black pieces blunder their defense playing 31. ... Kh8, and fall for a nice forced mate in 3: