"I firmly believe that any man's finest hour—his greatest fulfillment to all he holds dear is that moment when he has worked his heart out in a good cause and lies exhausted on the field of battle — victorious." - Vince Lombardi
Nothing feels better than taking on a challenge by working to the full extent of your physical abilities, and lying there exhausted after you've defeated it.
To me, that's the true definition of victory. The great competitors are able to do that, and in all facets of their lives.