Look with love upon an exceptional leg (4)
I believe the answer is:
ogle
'look' is the definition.
(I know this)
'love upon an exceptional leg' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'upon' is a charade indicator (letters next to each other).
'an exceptional' is an anagram indicator.
'leg' anagrammed gives 'gle'.
'o'+'gle'='OGLE'
'with' is the link.
(Other definitions for ogle that I've seen before include "Eye lecherously" , "Cast flirtatious glance at" , "Look at amorously" , "Gaze at lecherously" , "Close scrutiny" .)