Deuce means an ordinary tennis game has reached a level point score from which the standard advantage procedure requires a two-point margin to finish. A player can earn advantage and then lose the next point, returning the game to deuce. That is why one game can contain many more points than its compact scoreboard seems to suggest.
Read advantage as an opportunity, not a completed game
The player with advantage is one point from winning the game under the standard procedure. If the other player wins the next point, the game returns to deuce rather than ending. The scoreboard can therefore move repeatedly between deuce and advantage without adding a game to either player's set total. Watch the server indicator and player names so that the advantage is assigned correctly. A rapid commentary call can be hard to follow when the camera cuts to a replay.
Keep the set score unchanged until the game ends
A long deuce sequence changes the immediate point state but not the games-won column until someone completes the game. This can make the overall set graphic look static while the contest is intense. Do not assume the score has frozen. Notice the point display or listen to the umpire's calls. Statistics such as break points saved may accumulate during the sequence, but those are records of opportunities, not additional games awarded on the main scoreboard.
Check whether the event uses an alternate format
Some competitions or match categories use no-ad scoring or other approved procedures. In that case, a deciding point can replace the familiar repeated-advantage sequence. The current event rules determine which applies. Do not use a standard singles memory to overrule a doubles listing without checking. A point that appears to end a game suddenly may be exactly the announced format. Check the tournament, match category and score procedure together before applying a familiar deuce rule.
Understand the scheduling consequence
A game with repeated deuce can take much longer than a quick hold, so tennis start times for later matches remain estimates when they depend on earlier play. A listed not-before time is different from a guaranteed first serve. For a practical exercise, count the points from the first deuce until the game ends, then compare that sequence with the unchanged set score. The experience shows why a tennis match cannot be timed by multiplying an average game length by the remaining games.
Useful answers
Does advantage guarantee the next point ends the game?
No. If the player without advantage wins it, standard advantage scoring returns to deuce.
Does every tennis event use repeated advantage scoring?
No. Approved alternative formats exist. Check the current tournament and match-category rules.