Looking for a moment in a mecha anime with a girl battling

[KidEgo]

a guy in her mecha and kicking his ass. I've got a song in mind, but don't have an anime to go with it, and there has to be a mecha anime with a girl and a guy in a mecha battle with the girl winning.

[Mastamind]

Neon Genesis Evangelion. They don't really fight each other, but the second Rebuild movie has a scene where

Spoiler :

Shinji is forced to kill Asuka in her Evangelion.

[EkaCoralian]

In episode 42 of Eureka seveN, Anemone and Holland have a short battle against one another (as Holland is in her way because she's trying to get to Eureka and Renton.) Anemone ultimately wins by destroying Holland's mech in the end (and does indeed 'kick ass' since her mech contains a clawshot and several heat-sensing lazors. xD)

[CorpseGoddess]

If you wanted to do some editing using two different anime, Jo from Burst Angel fights in her mech a LOT.

[Kireblue]

Code Geass
Kallem kicks everybody's ass. (Jeramiah, Suzaku, Gino, and many more)
http://www.youtube.com/watch?v=mUZ5i4lvCzM

Bast of syndrome. I remember a girl being in this series with a mecha
http://www.youtube.com/watch?v=7R6eEZOOfHc
That reminds me, I gotta finish watching Bast of Syndrome