what is a winner? some say if it bounces twice on the opponent's court, it's a winner. what if the opponent is close to the ball but couldn't hit it or missed? And do service winners count as winners (like if the serve is touched by the returner but is not successfully returned?
The winner is the kind of shot that isn't touched by the opponent's racquet!
A service winner is either an ace or a serve which isn't returned... some tournaments do include service winners among winners and some does only count the winners!!
For the reasons stated it is too difficult to count. Some Wimbledon matches in the past counted second serve return errors as winners for the server whilst RG was counting only aces of the serve as winners. That leaves such a huge space for discrepency that this stat can't really be explored to great effect.
Champions deserve whatever they win playing within the laws of the game
Those numbers are wrong, they had some kind of bug there.
Final count is Isner 246 winners, Mahut 244, but I'm pretty sure aces aren't counted there. Including aces, that would be Isner 358, Mahut 347.