How to persuade her?

So, I'm involved in a sport (let's just say its soccer for arguments sake). I have a "friend" that plays soccer with me, and the only reason she started was because I did first. She has copied everything I've done since middle school, and at first I was flattered, but now it's getting very annoying. She's constantly competing with me to somehow prove that she's better. But here's the catch. She seems to be really into "tennis" (which I played before, but didn't like) but she hasn't been able to fully commit to it due to the soccer practices. I can tell she doesn't actually like soccer, and she just continues to do it because I'm in it. I'm thinking about trying to persuade her to drop soccer and fully take up tennis. But I don't know what she'll say since she's still completely obsessed with beating me at soccer. How should I go about this?
How to persuade her?
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