Tennis call Don overturned (3,2)
I believe the answer is:
Here is my best explanation:
'tennis call' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'don overturned' is the wordplay.
'don' becomes 'puton' ('put on' can be a synonym of 'don').
'overturned' says the letters should be written in reverse.
'puton' backwards is 'NOT UP'.
(Other definitions for not up that I've seen before include "with tennis call", "call in court" and "still in bed".)