What is no-ad scoring?
At deuce you play one point and that point wins the game. There is no advantage. The receiver picks which side to take it on, deuce court or ad court.
How the game is scored
A no-ad game runs love, 15, 30, 40 like any other game. The difference arrives at 40-40. In an ordinary game that is deuce, and somebody has to win two points in a row to get out of it. In a no-ad game deuce is a single deciding point: win it and the game is yours.
Everything else about the game is unchanged. The server still starts in the right half and alternates, faults are faults, and a let is a let.
One thing to settle before you start: no-ad is an approved alternative, not the default. Appendix VI says these methods may be used, so somebody has to have agreed it, whether that is the league, the event or the four of you at the toss. Turning up at 40-40 and announcing it is too late.
The receiver picks the side
The deciding point is the receiver's choice: deuce court or ad court. The server finds out where the return is coming from when the receiver walks over and stands there.
In doubles the receiving pair choose the half between them, but they cannot swap positions to do it. Whoever is already standing in the half they picked takes the point. In mixed doubles there is no choice at all: the receiver is the player of the same gender as the server, and again the pair stay where they are.
Why clubs play it
A deuce game has no ceiling. It runs until somebody wins two in a row, and there is usually another pair standing at the gate. No-ad puts a floor under how long a match can take, which is why it turns up on league sheets and at club nights.
What it costs you is the long deuce game people talk about afterwards. That is the trade, and it is a real one.
You will hear it called sudden death deuce
Club sheets, league rules and half the people you play call it sudden death deuce, or just the deciding point. The rule book calls it no-ad, and so does an umpire. All three mean the same point.
In the rule book
ITF Rules of Tennis, Appendix VI, under the “No-Ad” scoring method:
If each player/team has won three points, the score is “Deuce” and a deciding point shall be played. The receiver(s) shall choose whether to receive the service from the right half or the left half of the court. In doubles, the players of the receiving team cannot change positions to receive this deciding point.
Common follow-ups
Is the score still called deuce in a no-ad game?
Yes. The rule book keeps the word: at three points each the score is deuce, and the next point decides the game. Plenty of umpires add “deciding point” after it so nobody is in any doubt about which kind of deuce this is.
Can the server choose the side instead?
No. The choice belongs to the receiver, in singles and in doubles. In mixed doubles nobody chooses: the receiver is the player of the same gender as the server.
Does no-ad change anything else about the match?
No. Sets, tiebreaks, change of ends and the serving order all carry on as normal. Only the game at 40-40 is different.
We forgot and played it as advantage. What now?
Usually nothing turns on it. Whoever won the first point after deuce is whoever no-ad would have given the game to, so if that side went on to take it anyway, the game is theirs either way, and Rule 27’s principle that all points previously played shall stand covers the extra point. If the other side ended up with the game, the rule book does not answer you: Rule 27 lists corrections for serving out of turn, the wrong half, the wrong ends and the wrong kind of set, and not for the scoring method inside a game. With an official on court it is the referee’s. Without one it is your league’s rules or an agreement between you, which is the argument for saying no-ad at the toss rather than at 40-40.
Luasc plays no-ad if you switch it on and calls the score “deuce, deciding point”. On that point the watch will not tell you deuce or ad, because the side is the receiver's to choose and not the app's to announce. See how it scores the rest.