Originally Posted by TennisPhan
lol, who's gonna beat her 87% 1st serve when she's on? unbeatable when she's on.
Still struggling with the distinction I see.
Definition of unbeatable: "Impossible to defeat or surpass"
Federer could beat her, Djokovic could beat her, Nadal could beat her. Historically there are quite a few women who at their peak would have won at least some of the time against peak Serena. Ergo, she's not unbeatable. She's just difficult to beat.
Btw, the question in the OP was "Is Serena unbeatable when not injured", not "Is Serena unbeatable when she hits 87% first serves".