I have a pick with which you guys may not agree but I am seriously thinking that way, Djokovic didn't play best vs Simon this week, so my prediction is, Nishikori to win against Djokovic !
O hero betting if you bet big amount money on nishikori, the odds is 6 to him, and 1.1X for djokovic for the match winner, imo i will pick djokovic cause he is still the best, simon is not a weak player, he has very good baseline skills and defense is as good as djokovic, that's why they played very hard yesterday, but betting a little on kei nishikori may be a surprise, cause he beat djokovic in US Open 2014, so tennis is what amazing happens