A knight for a Sac

Robbie,

I was curious about your thoughts on black's 24th move Qg5. Previously he could not take the pawn on g6 because of the imminent biship Q/K pin (yikes! what a gorgeous threat.) After Rf1, however, what's to stop white from taking pawn and offering a Qtrade? I ran this through chessmaster vs. chessmaster, 3 secs per move, and black wins! Obviously a longer time constraint could have led to a white win but, to me, Qg5 was the game's decisive error.

test livechess 2 please http://www.chess.com/live

mjl4871  sorry for the wait...  In the exchange yes, before the king moved, the white bishop, threatened that pin so, that threat was removed when Q-G5 couldv'e been replaced with the pawn take... 

So I decided to import that key position into ChessMaster also to see the results...  I waited about 5-10mins to get a good depth.. About equality, white small edge.