Are up, first, against a woman (4)
I believe the answer is:
vera
'a woman' is the definition.
(a woman's name)
'are up first against' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'are' is 'era' which is located in the answer.
'against' could be 'v' (abbreviation for 'versus') and 'v' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for vera that I've seen before include "A girl to rave about" , "Duckworth, Lynn" , "senior songstress?" , "Woman" , "Woman's name" .)