I ended up backing Nadal from the start. This didn't go well as Murray took the first set in a late break of serve. Instead of laying for a loss I backed Nadal further. I did this because he wasn't playing all that well and Murray was playing really exceptionally. I knew the tide for both of them would have to change and sure enough it did. Nadal started playing better and Murray started playing much worse.
Tomorrow I'm going to back Maria Sharapova from the beginning of the match and lay when I have a 15% profit.