Between Rafa and Djokovic.
Many people seem to think that Djokovic is the offensive player and that Rafa is the one who does all the running, but the statistics (at least some of them) seem to suggest otherwise.
This is from the Wimbledon final, somewhere in the middle of the match. I don't have one for the entire match.
And this one from the AO is more impressive, because Rafa actually spent more time on court during the entire tournament (not taking the final into account)
I've looked at the duration of their matches and it's
Nadal - 993
minutes - 13.83
Djokovic - 898
minutes - 15.79
Does anyone have statistics from other tournaments/matches?