Your opinion doesn't define proof. If you have proof then others couldn't credibly disagree. Declaring someone a great coach is one opinion. Taking some limited sample of games and holding it up as an unassailable indicator is Cliff Clavin wild bar talk.

My opinion is great coaching has little to do with the little decisions that go on during the 40 minutes of play. It has a great deal to do with leadership of the program as a whole that inspires the confidence in others to invest time, effort, money, and facilities; i.e. great players, the University President and his colleagues, the AD, assistant coaches, donors, and more. It has has to do with having great vision and the right vision and philosophy of utilizing those resources to play the game with a superior strategy and so much more.

Great coaches do more often win tourney games. They play better during the entire year and gain great advantage in the seeding system and have the probablities on their side.

This is opinion and may not be entirely correct but i think clutchness is crap.

BTW, K. C. Jones was the second greatest player in NBA history to Bill Russell if the standard is NBA championships won.