from that document...
Between points, a maximum of twenty (20) seconds is allowed. When the
players change ends at the end of a game, a maximum of ninety (90) seconds
are allowed. However, after the first game of each set and during a tie-break
game, play shall be continuous and the players shall change ends without a
But that is the rule for ITF events. Nadal plays ATP events and from Wikipedia
A tennis match is intended to be continuous. Stamina is a relevant factor, so arbitrary delays are not permitted. In most cases, service is required to occur no more than 20 (ITF events) or 25 (ATP and WTA events) seconds after the end of the previous point.
So, it is 25 seconds between points. Now, the point (pun intended) is when does a point finish? When the error or winner is hit? When the player gets the ball from the ball boys? Anyone care to explain?