Chess Blindness of the Champions
Yes, it can happen. Even at the very pinnacle of chess, a blunder can be made and the opponent misses their opportunity. Game 6 of the World Championship match in Sochi, Russia, saw it happen. Magnus Carlsen had a winning position and blundered. Vishy Anand missed a rather obvious combination that many improvers would have seen and eventually lost. As Carlsen said during the interview after the game, he was very lucky that day.
Click here to read about this and other examples of chess blindness among the greats of the game at ChessBase.com.