The serve is the only shot in tennis you fully control. Your stats should drive every decision about how hard, where, and with what spin you hit it.

The two numbers that matter

First-serve % (how often you make it)
First-serve points won % (how often you win when you make it)

The classic trap

Players obsess over first-serve percentage. They slow the serve down, get to 75% in, and win fewer points because every first serve is now returnable. The right target is to maximize first-serve points won × first-serve %.

A 60%-in / 75%-won serve produces 45 points per 100. A 75%-in / 60%-won serve produces 45 points per 100. Same outcome — but the slower server then faces tougher second serves on the 25% of points they missed.

Second-serve math

Your second-serve points won % is the floor of your service game. If it's below 45%, you cannot consistently hold serve against a competent returner. Above 55% and you'll hold most of the time even with a mediocre first serve.

What to do with your numbers

First-serve % below 55% → slow down 5%, prioritize placement
First-serve points won % below 60% → speed up or change placement, you're too readable
Second-serve points won % below 45% → add spin, this is the #1 fix
Double-faults > 4 per match → your second serve is a "safe push" — commit more

Track these for 20 matches. The right service-game adjustment will become obvious.