Beautiful Ali

This wonderful dog is a star in the Agility classes.  Her owner is a friend and photographer but asked me if I'd like to take some shots as the dog won't run for anyone else.  Ali is a very fast Bearded Collie and, with her long hair flying everywhere coupled with very dull light, I found this very challenging. I pushed the ISO up high as I had to have a very fast shutter speed - even so, there is still some blurring.  
I hope to have another chance to better today's efforts - noisy and not always focussed accurately.
Anyone with tips please?  I'd like to get some focussed, sharp shots next time.