Here's my breakdown.
Superman's advantages:
1. Strength
2. Durability
3. HV
4. Freeze breath
WW's advantages
1. Fighting skill
2. Lasso
3. Tiara
Skill would make WW get more hits on Superman than Superman gets on her.
Lasso is an option after WW stuns Superman will a nerve blow.
Tiara is an option after WW stuns Superman with a nerve blow.
Freeze breath is an option that can be done at any time
If characters, job, and have PIS then Superman wins everytime.
If characters fight to the best of their abilities then Superman wins because of the freeze breath tactic.
If freeze breath isn't allowed (or Superman decides not to use it) then WW will win a majority by applying the stun hit and lasso tactic.
So Superman wins via freeze breath or Diana wins via lasso.