When tennis can go to the devil? (5)
I believe the answer is:
deuce
'the devil?' is the definition.
(euphemism for the devil, as in 'what the deuce')
'when tennis can go' is the wordplay.
I cannot really see how this works, but
'when' could be 'e' (I've seen this in other clues) and 'e' is found within the answer.
The remaining letters 'duce' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for deuce that I've seen before include "score, forty apiece" , "A two; forty all" , "40-40 in tennis -- 2 in cards" , "Dickens" , "Two in cards or dice" .)