Start a tennis match (5)
I believe the answer is:
serve
'start a tennis match' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for serve that I've seen before include "Work for; tennis stroke" , "Act as waiter" , "commence action in court before judges?" , "Attend; start to play tennis" , "Put the ball in play in 7 down" .)