Hi, I am learning English, and I encountered some problems with English expressions. Could you help me and explain these phrases for me in English?

1. sb is 500/1 to win.   

Does this mean that someone is so strong that it's easy for him/her to win? 

2.The Australian Grand Prix definitely shook up the established order in the paddock. Will this season really be as open as some are predicting?

I read this sentence in F1 forum. I had a problem in understanding the meaning of "open". Why use "open" to describe sports events? 

3.That unpredictability saw not one of the main expected protagonists win in Melbourne but instead Adrian Sutil, a most unlikely of winner.

This sentence is about F1 as well. Does it mean that Adrian Sutil win instead of some protagonists, which is unpredictable?

4.It was a surprise to many in the paddock to see Daniil Kvyat on the top step of the podium in Australia, but the young Russian tore up the formbook and produced an excellent display.

There is a phrase "tore up the formbook". I have no idea what it means.(⊙︿⊙) What the formbook is?

Please help me. Thank you so much.( ^_^ )