First love found by girl in a novel (8)
I believe the answer is:
original
'first' is the definition.
('original' is associated in meaning with 'first')
'love found by girl in a novel' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'found by' means one lot of letters go next to another.
'novel' indicates anagramming the letters.
'girl'+'in'+'a'='girlina'
'girlina' is an anagram of 'riginal'.
'o'+'riginal'='ORIGINAL'
(Other definitions for original that I've seen before include "New in character or design - not a copy" , "Not derived or copied from anything else" , "In first form" , "New and unusual" , "First; (an) odd character" .)