I've heard it said that champions like Michael Jordan, Tiger Woods, Sampras, etc. are motivated more by avoiding the feeling of loss than by than having the feeling of winning. They are motivated by negative emotions rather than positive. That jibes with this anecdote IMO.
I would probably congratulate myself on 4 out of 5, which is why I'm not a champion :)
Champions don't fear loss otherwise they would never try for the last second winning shot. Champions like Michael Jordan, etc, believe they should win every single time because they are the best. When they take that last second shot, they believe it is going to score. A championship is theirs for the taking and if they lose, it's because they fucked up, not because someone else beat them.
[1]http://www.npr.org/templates/story/story.php?storyId=2406852...
Tennis is a sport where you will rue every single point in a lost match. It lends itself particularly well to the if-only-I-did-that-one-thing-differently rationalization. It is due to the hierarchical (game-set-match) nature of the scoring and how one only needs to win one crucial point to get past their competitor (e.g. at 30-30, 30-15, the players are really sitting on a knife's edge).