Loves extended tea (6)
I believe the answer is:
oolong
'tea' is the definition.
(I know that oolong is a type of tea)
'loves extended' is the wordplay.
'loves' becomes 'oo' (love means 0 in tennis).
'extended' becomes 'long' (extended can mean longer than usual).
'oo'+'long'='OOLONG'
(Other definitions for oolong that I've seen before include "Kind of China tea" , "sort of leaves" , "oriental tea" , "Chinese tea leaves - no logo (anag)" , "Kind of Chinese tea" .)