Does, when one plays the first shot (6)
I believe the answer is:
serves
'does' is the definition.
('serve' can be a synonym of 'do')
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for serves that I've seen before include "What a waiter does" , "Puts the tennis ball in play" , "Strokes that puts the ball in play" , "Puts the ball in play on court" .)