RULES OF TENNIS 2017 - RULE 3. THE BALL
Balls, which are approved for play under the Rules of Tennis, must comply with the specifications in Appendix I.
The International Tennis Federation shall rule on the question of whether any ball or prototype complies with Appendix I or is otherwise approved, or not approved, for play. Such ruling may be taken on its own initiative or upon application by any party with a bona fide interest therein, including any player, equipment manufacturer or National Association or members thereof. Such rulings and applications shall be made in accordance with the applicable Review and Hearing Procedures of the International Tennis Federation (see Appendix X).
The event organisers must announce in advance of the event:
a. The number of balls for play (2, 3, 4 or 6).
b. The ball change policy, if any.
Ball changes, if any, can be made either:
i. After an agreed odd number of games, in which case, the first ball change in the match shall take place two games earlier than for the rest of the match, to make allowance for the warm-up. A tie-break game counts as one game for the ball change. A ball change shall not take place at the beginning of a tie-break game. In this case, the ball change shall be delayed until the beginning of the second game of the next set; or
ii. At the beginning of a set
If a ball gets broken during play, the point shall be replayed.
Case 1: If a ball is soft at the end of a point, should the point be replayed?
Decision: If the ball is soft, not broken, the point shall not be replayed.
Note: Any ball to be used in a tournament which is played under the Rules of Tennis, must be named on the official ITF list of approved balls issued by the International Tennis Federation.