In my opinion, the way a person handles themself in a moment like this is one of the most telling signs of what the individual truly stands for. A true sportsman should be gracious in defeat, and should also be able to enjoy victory without disrespect for their competitor.
Many years ago, my HS band was a consistent winner at the local, regional, and state level. Our director demanded that we handled ourselves with class, and that we respected our competitors. When we won, we had absolutely no public celebration in front of our competitors, those moments were enjoyed amongst ourselves, after the competitors were gone. When we lost (which fortunately was rare), we graciously and sincerely congratulated our competitors, and saved any negativities for later, amongst ourselves. While this may all sound a little extreme, especially in contrast with the atmosphere surrounding pro sports today, I believe that valuable lessons were learned, and strong values were instilled in us as individuals. Very often, when we happen to get together with old friends and talk about how things were "back in the day", we recall how proud we were not only of our victories, but how we handled ourselves publicly, be it in victory or defeat.