22. Ball Falls on Line
A ball falling on a line is regarded as falling in the Court bounded by that line.
USTA Comment: In a non-officiated match, each player makes the call on any ball hit toward his side of the net. If a player cannot call a ball out with certainty he should regard it as good. In doubles, normally the Receiver’s partner makes the calls with respect to the service line, with the Receiver calling the side and center lines, but either partner may make the call on any ball he clearly sees out.
26. Score in a Game
a. If a player wins his first point, the score is called 15 for that player; on winning his second point, the score is called 30 for that player; on winning his third point, the score is called 40 for that player, and the fourth point won by a player is scored game for that player except as below:-
If both players have won three points, the score is called deuce; and the next point won by a player is scored advantage for that player. If the same player wins the next point, he wins the game; if the other player wins the next point the score is again called deuce; and so on, until a player wins the two points immediately following the score at deuce, when the game is scored for that player.
27. Score in a Set
a. A player (or players) who first wins six games wins a set; except that he must win by a margin of two games over his opponent and where necessary a set is extended until this margin is achieved.
28. Maximum Number of Sets
The maximum number of sets in a match shall be 5, or, where women take part, 3. [what?]