Love to leave haven unchanged (2,2)
I believe the answer is:
as is
'unchanged' is the definition.
(I've seen this in another clue)
'love to leave haven' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'to leave' indicates named letters should be taken away.
'haven' becomes 'oasis' (synonyms).
'oasis' with 'o' removed is 'AS IS'.
(Other definitions for as is that I've seen before include "In the current circumstances" , "not changed" , "without change" , "unaltered" , "unchanged" .)