Ultimately, the reason why Djokovic's prospects haven't changed is that he is still likely to face Nadal in the quarterfinals, and Federer or Murray in the final. Furthermore, the top three players in the world (Djokovic, Federer and Murray) have a combined 90% chance of winning the tournament, while Nishikori's prospect prior to Monday was a mere 3.8%. Should Federer or Murray have suffered an upset in the first round, Djokovic's title chances would have definitely skyrocketed.
Nishikori's early exit also raises an interesting question - which player will emerge from that quarter? Our model suggests that Marin Cilic, the reigning US Open Champion, and not David Ferrer, the highest seed left in that quarter, has the highest odds. This may to due to the fact that Ferrer has not won a match since Roland Garros, and Cilic had recently reached the quarterfinals of Wimbledon.
Despite ranking outside the world's top 40, Benoit Paire has a decent chance (6.4%) of reaching the semi finals. As our model rewards players who pull off upsets, Benoit Paire's rating increased greatly after his first round win over Nishikori, making him the fifth favorite player to come out of this quarter of the draw. Also look out for dark horse Jo-Wilfried Tsonga - while he has dropped to as low as 18th in the world, his semi-final odds are only a tad lower than Ferrer's as a result of his strong showing in Montreal.