After watching two punishing duels on the Australian Open over the past two nights (Monfils/Simon and Djokovic/Wawrinka), I can only arrive at this conclusion.
Tennis is a non-contact ball sport designed for endurance and skill. The objective of the game is to defend, outwit and outlast your opponent. Force them into mistakes, and the win will come in time. The problem is staying alive until then.
That is all.
*Hat tip to tennis players all over the world, you guys are playing a sport I deem as suicidal. Basketball for example, would never involve five hours of exertion even in overtime. This game is plain out insane.