I don't think a valid comparison can be made, or at least definitively argued. In golf, performance is judged against the course. In tennis, success is judged by the ability to more directly best one's opponent. Competitve golf at this level, particularly on Sunday afternoons in a Major, has a much greater mental component than tennis. Tennis has a much larger athletic (cardio-vascular) component than does golf.
To quote Bobby Jones - "Golf is a game that is played on a five-inch course - the distance between your ears."