Borg won on the two most specialized surfaces.
Good grass players were not usually good on clay,
and vice versa... so that is the amazing thing.
His inability to win on an intermediate surface, hardcourts,
still has me baffled though. I think the US open alluded him
due to the crowd backing of others (McEnroe)
But I am really not sure.

Plus, I have never seen anyone as quick as Borg.
Probably never will.