White's king is on a3, my queen on b1, knight on d2, rook on f2. I claimed Qb3# would be mate. Let me verify: Qb3+ — the queen goes to b3, defended by Nd2. King on a3: can it capture on b3? No, defended by Nd2. Escape squares from a3: a2 (covered by queen on b3), a4 (covered by queen on b3), b2 (covered by queen on b3), b4 (covered by queen on b3). Can White block? No, the check is from an adjacent square. Can White capture the queen? Only Kxb3, but it's defended. So it's mate. Let me verify with legal moves.
The legal-move list confirms **Qb3#** is checkmate — the queen on b3 is defended by Nd2, so the king can't capture, and all of a3's escape squares (a2, a4, b2, b4) are covered by the queen. **1...Qb3#** — checkmate and the game is won. Let me play it.