The market was incorrectly set to close on the 17th. This meant people were still betitng on the outcome during the match and even after the result was known. We have no real way to determine the precise times bets were placed so we had no alternative but to void the market.
How did it happen? The market was created based on incorrect information which told us the Davydenko match would not be played until Thursday.
I apologise if you picked the winner correctly.