I'm a martial arts enthusiast currently fighting regularly and training as a semi pro the UK.
People have been trying to beat eachother with sports for a long time. After a basketball game the loser can look to the winner knowing if they fought, he'd beat the man who just scored the winning points. No fighter lays there on his back after a fighting thinking "yeah i got beat, but I could whoop that guy in a basketball game."
Fighting is the ultimate expression of physical competition requiring a balance of mental and physical strength to compete at the highest level.