You can't blame him because he's undersized for a tennis player. The big 4 are bigger, stronger, and have weapons. He's a workaholics, but nothing he can do when he gets overpowered. And he knows he's overmatched.
Tier1(goat): Federer; Tier 1.5: Laver, Gonzales, Sampras, Nadal, Borg;
Tier 2: Lendl, Connors, Rosewall, Tilden; Tier 2.5: McEnroe, Agassi