This may have been true at one time, but not anymore... Darren Clarke beat him in the match play, Hal Sutton beat him at the Players. (not majors but very big events) And this was when he was dominating the tour. Nowadays guys know they can beat him... If anything Tiger fell apart at the end...2 up with 2 to go and he goes bogey, bogey... come on!
Also I don't think he has ever come from behind on in the final round to win a major, granted if he's leading after 54 I think has has always won, so nobody has ever come from behind to beat him either. But if he's really in their heads there should be some examples of him putting a number up on sunday and the leaders falling apart.