The serve is only a setup for the shot after it

Aces are a rounding error in most matches; what decides a service game is where the third ball lands.

Count the free points in a typical professional set. Even for a big server it is a minority of the service points, and for most of the draw it is a small minority. The rest of the time somebody gets a racket on it, the ball comes back, and the server has to play tennis.

That third ball is where service games are actually won, and it is the least discussed shot in the sport.

The pattern is simple to describe and hard to execute. You serve wide to pull the returner off court, which mechanically constrains where their reply can go, and you have moved before they hit it because you already know the answer. Then you hit into the space they vacated. The serve was never trying to be a winner. It was trying to make the next ball predictable.

Which reframes what a good serve is. Not the fastest one. The one whose reply you can forecast.

That is why serving into the body is underrated and underused. A ball at the returner's hip jams the swing, forces a cramped block, and produces a floating reply into the middle of the court almost every time. It gives up pace and location glamour and buys you a known, weak, central answer. Against a returner with long limbs and a full backswing it is worth more than another five miles an hour down the tee.

The other thing that shows up when you watch service games this way is how many players have no plan at all. Big first serve, returned, and then a startled forehand hit from a stationary position because the server was watching to see if the ball came back rather than moving on the assumption it would.

I would go so far as to say that if a player is standing still when the return is struck, the serve failed regardless of how fast it was.

There is a scouting layer on top. Because serve-plus-one patterns are habitual, they are the easiest thing in tennis to prepare for, and a returner who has done the work is not guessing at the serve. They are standing where the third ball is going to be sent, which is a much easier thing to predict than a serve, and a much more damaging thing to get right.