You lose 11–9 and spend the drive home replaying one shot. It feels like that shot decided the game. Usually it didn’t. Between even teams, a close game is close to a coin flip, and what tilts it is a small edge built over every rally.
To put numbers on it, we simulated hundreds of thousands of doubles games under standard side-out scoring, to 11 and win by 2. Each rally is a weighted coin: the serving team wins it with a set chance. In a 2025 study of 510 serves in amateur doubles, the serving team won about 42% of rallies, so we started near there, at 45%.
Even teams split the close ones
When both teams win 45% of the rallies they serve, about four games in ten end within three points (39.6% in the model), and each team wins half of them. Serving first makes no difference: the team that serves first wins 50.1% of games.
A small edge, a real difference
Now give one team a little more on its serve, with the other team still at 45%:
| Rallies you win on your serve | Games you win | Close games you win |
|---|---|---|
| 40% | 35% | 42% |
| 43% | 44% | 47% |
| 45% | 50% | 50% |
| 47% | 56% | 53% |
| 50% | 64% | 57% |
| 55% | 75% | 64% |
Win two more rallies in every hundred you serve, 47 instead of 45, and you win 55.5% of games instead of half: five or six more wins in every hundred games, from a change too small to notice in any one of them.
It works the same on their serve. Win 57% of the rallies they serve instead of 55%, and you win 55.9% of games.
Why it feels like one shot decided it
At 45%, each team gets about six serve turns a game, and a serve turn is worth about a point and a half (1.59 points in the model). A close game comes down to one or two of those turns going one way or the other. The last one is the one you remember, but the game was built across all of them.
What to watch instead
So the useful number isn’t whether you won the close one. It’s how often your team wins the rally when you serve, and how often when they serve, across many games. They tell you different things:
- On your serve: these are the only rallies that score. Every one you win is a point.
- On their serve: these rallies win the serve back. Win more of them and their serve turns get shorter.
Here’s a real example. In one of Brad’s sessions on 19 October 2026 (Brad builds Rally Trace), his team won 39% of the rallies on its own serve, 29 of 75, and 59% on the other team’s, 47 of 79: 49% overall. The receiving was strong. The serve was where the points went missing, and no single shot would have shown that.
One close loss is noise. A month of serve and receive numbers is a pattern you can work on.
Seeing it in your own games
Rally Trace counts these from the score you keep on your Apple Watch. Tap the side that won each rally, and your iPhone shows how each game swung. With Rally Trace Pro, each game also shows how often you won the rally on your serve and on theirs, and how each of you did on your own serve, and History shows your win rate month by month.