Even Masters Blunder Once (or TWICE) In a While

The illustrated position represents Joel's Mastery in that he obtained a two pawn advantage over me in some 48 moves. However time was running short, My opponent's King was exposed, and I had just enough play to warrant the withholding of my resignation. I played b4. Even though my opponent was low on time, he should have thought a little longer than he did. His blunder of cxb4 came almost immediately, and afterward he admitted that he completely overlooked the purpose of b4, namely Removing the Defender of the d4 square. I played Rd4! and just like that I salvaged the game.

However, my opponent inexplicably blundered again by playing Rdd8?? This allows Mate in two moves. I am guessing he missed the mate but saw the discovered check. I'll bet he thought I would play Nxd6+ and after Kf6 NxR. But who needs to win the Exchange when you can win the game? I had to look at it three or four times, because I could not believe my eyes; or even my own voice when I played Ne4 and said, "Checkmate."