Interesting Tactic

I was on FICS again this morning and played a 1300++ rated player.

We arrived at the position shown.

I am Black. White had just played
28. Rd1
placing my Queen under direct fire.

I knew that if we trade pieces, I have an advantage all the way to the endgame.

So after much thinking, I played the move.

28.... Qf4!

A very surprising move. I loaded this into Fritz and Fritz didn't even consider this move. But tactically it works.

White cannot play Bxd5. The Knight on d5 is forbidden fruit.

The reason I can play this and not worry about the Knight is because White has a back rank problem and is weak on the dark squares.

Let's say White plays
29. Bxd5 Rxc1 (2nd diagram)

Now the situation's very clear.

White now must play

30. Rf1 (Rxc1 leads to mate after Qxc1 while Qxf4 is also impossible because of Rxd1 leading to mate) Rxf1+
31. Kxf1 Qxe4
32. Bxe4 Rb1 (and Black has a decisive material advantage going into a R v B endgame with a passed a-pawn)

My opponent didn't play this series of moves btw.