There's combat and then there's mortal combat.
Tennis allows for the psychological strains of one-on-one combat minus the threat of annihilation or permanent physical injury, though I've seen psychological injuries result at all levels. Some are never the same after a certain loss.
Martial arts can be to the end, but primarily it is just pain or possibly permanent injury at risk. Then there is actual mortal combat with loss defined as death. None of the rest truly compare.
I like to think of elite coaches as World Class Chefs while others know how to run a fast food joint and put out the volume with palatable results that fill stomachs on the cheap. You need the spectrum. You even need so-called inferior coaches just as much as you need people with quirky personalities so you have a basis and reference points for judging the norm. If you have a norm in a skill set, then you can judge the superior ones and even the brilliant. Should we only allocate court time for players and teachers above a certain skill level? We need anyone willing to share the game with others, and even volunteers with limited skills and knowledge have a place just like parents coaching kids as volunteers. I had a former college player as a team coach once and I learned little from him while a music teacher volunteer turned out the be the one who got all the kids out to play, including me. I suggest that it's best to help other teachers move forward and not drive them out.
Landsorp on American Tennis Coaching
Yes, Novak is acrobatic much like a flier might maneuver his aircraft. He maintains improbable balance under almost all conditions.
Exemption for AO?
They should give him one since he's had health issues prior to this with food allergies.
Federer wins in this important statistic
Maybe we should just go with the most Sportsmanship awards as the deciding statistic. As for winning percentages, why stop at the Open Tennis Era?