Absolutely true story: A friend of mine could make a golf ball do just about anything and was a wonder to watch. He was a scratch player or better (I don't recall his exact handicap). On paper, he was professional standard. He could sink 10 foot putts all day long (my hyperbole), but what he could not do was sink a 10-foot putt, when it counted . By his own admission, he just did not have the match temperament to per…
Nick Faldo did an interview with Joe Buck where they touched on the subject, and he said without the complete conviction that you're going to sink the putt/make the birdie/win the tournament - you'll never accomplish any of it.
At the Pro level, the mental aspect of the game is more important than the physical.