
Id give a silent "fuck you" moment and let her know your not bothered by the shit she does, and that its your turf the game is being played on, not hers.
That and #2 move would be next time she teases you, straight up call her out if everyone else is around listening as well. Need to project to her, and onlookers that shes the one infact hitting on you but just not coming clean about it.
I'd say something up front, and keep up the confident attitude:
"Hey are we back in grade school with this ::mock something here that she just said::?, I thought girls only do that kind of stuff when they have a crush on a guy"
::her dumb negging response
"Oh i see it has to be in dumb grade schooler talk...Do you like me like me?
What does she say to you, im curious?