Find the decisive blow (difficulty 1035)

12345678 hgfedcba

Black to move

Show solution
12345678 hgfedcba
  1. f1–d1 key move
  2. f2–d1
  3. g1–d1

What makes it

Mate in two, bought with a queen sacrifice. The shot starts with the queen. Rated 1035 — a solid test.