'the best film I ever made'?

If so, that would be in accordance with his belief that whatever he had just accomplished was his best work--to have to admit that he never achieved the artistic success of his very first film would, I think, be an impossible admission for any artist, let alone one with Welles' ego (this is not a criticism).

Also, if he said it in 1964, that was well before he made Chimes at Midnight, which he had every reason to claim as his best work (which I think he also said, and with which I agree).