Connors and Borg on the men's side. Chris Evert on the women's slide. Connors in 74 left no doubt, and I think the same could be said in 76 and 82. Evert dominated women's tennis from 75-78 and reigned supreme. Borg was clearly the top player in 79 and 80.
I think maybe Becker in 89 and Edberg in 91 are good choices too.