4 YR Thoroughbred OTC...has issues with other horses in the ring.?

Heyy, I have a thourobred too!(: She used to be like that, I am not sure of her history either, But How I fixed it, is I had my friends walk, trot, Canter and then gallop Past her while I was on her, She is very competitive and wants to race them, (she might be off the track, not sure) but anyways, I held a tight rein, sat deep in my saddle, and put my heels down in the stirrups, and everytime she tried to go forward, I would make her back up 3 steps, every step she took was another 3 back, and then soon enough I worked with her everyday and now you an do anything around her and she is just fine(: I hope I Helped!(: Good Luck!