what would you do? (it's a little long, sorry)UPDATE (THANK YOU ALL TOO)

UPDATED:  We had our most recent game yesterday, the crap started again, within minutes of our warm ups, at this point I could tell her mother was talking much louder behind me with other parents... it was clear to me this was my opportunity to handle this as best I  could.  So, right as she attempted once more to kick my child's call away again; and as my child looked up at me and was about to tell me what just happened, I calmed her with my hand, and abruptly took a handle of this situation... I stopped, sternly said her name, she looked again like a child that was busted, but then was trying to back out of her trouble... I said, NO MORE, she tried to say something, I cut her off, I seen what you were doing, and I explained it was not going to happen again, she gave me a look of "that's what you think" I simply walked closer to her, smiled my best smile and said: "look I know you think it's quit funny to do this, I have seen you do it on several occasions, today being enough, if you choose to do it again, you WILL be the one running after it; I do not appreciate this, and while you are on this field, you are on my team, and that means you will work harmoniously within this team" I asked her if she understood, she tried to say something, I said, there wasn't a reason for this attitude, and it will stop now.  She initially seemed to not be sure how to take what I told her, then she said "ok".  Our game went well and my team worked well together and she never tried once to be aggressive to any of of her team mates!  YEAH!!! I cannot tell you how happy I am to have (hopefully) a happy ending to this.  I appreciate everyone's posts and your words, it helped me realize I wasn't wrong... thank you all!

I am coaching my daughters team, it a U6 AYSO, 4 & 5 year old girls soccer team.  Sierra loves playing, loves to work within the team; she isn't the best on the team, but, she does make up for the lack of skills with the love.  The team for the most part is a great bunch of little girls.  I enjoy coaching and am glad this is something my daughter and I have enjoyed together.  This year, we had one team mate from last years team and the other 3 girls are new to us and the game. 

One is a difficult and hateful child at times and her parents don't seem to think she is being mean or could care less...they seem to laugh off her bad behavior.  She honestly reminds me of that little child that is the playground bully!? She lacks muster, it really seems she is doing this for her parents and not because she actually loves it. 

That being said, I have had my hands full with trying to get her to work with the team.  She is lazy, she doesn't hustle and doesn't listen to me, rather she looks in my general direction and then just laughs and rolls her little eyes at me.  I have tried to let it go... but, for the past two weeks of practice and then this past Saturdays game she has started to take things out on a couple of my girls on the team... unfortunately, one of them and it seems the brunt of her hateful nature seems to me Sierra, my daughter. 

I thought it was just me... being her mom and all and tried to keep an open mind.  That is until Saturday when my hubby that didn't know any of them well this year... was watching them all warm up and was appalled by this girls behavior and specially towards Sierra.  I had to remind her that day that we were a team and her kicking Sierra's ball out of bounds every time she came near Sierra wasn't being a team member.  She rolled her eyes at me and then smart mouthed me. 

Today was practice, and as soon as this girl arrived she began tormenting my daughter!  I now realize I am not making this all up... I stood there and watched her 3 times go straight to Sierra and kick her ball away, Sierra asked her every time not to do that... but she just laughed at Sierra and kicked it away and then kicked that ball way out far from our practice field... after the 3rd time I had enough; the girls all of them were playing a game called shark, one girl is w/o a ball and trying to kick the balls away from the other girls, who ever get the ball kicked away is now the shark... well, even when this girl wasn't the shark she still tried on several occasions to kick Sierra's ball away, Sierra was getting frustrated, and I finally called this girl on her attitude, and reminded her that she WAS NOT the shark... she just looked at me like I caught her in the cookie jar! 

She was relentlessly after Sierra the rest of practice.  I finally had enough and told her it wasn't nice to kick Sierra's ball so far away... I finally told her to go and get the ball if she was going to kick it that far away.  I know this might sound petty of me, but, I am telling you ladies I do not allow Sierra to be mean in any way towards any kid... specially her other team mates, I want them to all understand that they are team mates and they should be working together.  This child doesn't get it, and her parents seem to hear me every single time I attempt to say something to this girl... for the most part they just laugh it off like "good luck making her mind you"... like they can't get her to do what they want... why should I expect any different?! 

We still have 3 more games and 2 more practices... and I am wanting to defend my child; I can see how hateful this girl is... she is also nasty to a couple other girls on the team too... but Sierra gets the brunt of most of it.  I swear I know I cannot be the only person to see this attitude, but, maybe I am the only one that seems to think it's an issue?   I can tell you what I honestly wanted to do with her... kick her off, bend her over my knee... send her home until she can be nicer, make her aware that I wasn't going to put up with her crap... but, besides being mychild's mother I am all of there coach... Am I in the wrong?