This app is perfect for tracking your tennis match and your workout. Your match contributes to your rings (HealthKit integrated).
It supports tie-break (6:6) and champions-tie-break. You can also see side and who is the server.
At the end of match you will get a summary including set points.
(Fits all common sizes including Apple Watch Ultra)

Game modes:
+ Training - endless mode with heart rate
+ 1 Set - with heart rate
+ 3 Sets - last set is for champions tie-break
+ 5 Sets - last set is for champions tie-break

Functionality:
+ Single tap - Increase score
+ Double tap - Decrease score
+ Long press - Change who serves first (at start of match, otherwise its random)
+ Start/Pause Training
+ View current set points and separate view for current game

End result will be saved to workout (Health App -> Share -> Apps -> TennisClicker -> Data collected by TennisClicker -> Trainings -> Result)