The Stalemate Defense

The following position happened during the US Championship of 1951, which resulted in a victory for Larry Evans. Max Pavey (1918-1957), an American Chess Master and Medical Doctor, completely outplayed I A Horowitz. Black finds himself two Pawns and the exchange ahead, he also has a passed b-Pawn three squares away from Queening. Why hasn't White resigned? well, he sees a microscopic possibility of escaping defeat, using a nice swindle which involves the old stalemate trick. After capturing a Pawn at f4 with check, Black thinks it's all over, it's all over alright, but not as Black anticipated. Observe what White does.