It is resounding defeat Djokovic against Istomin. Djokovic will lose 1955 points compared to last year. If Murray wins the tournament will have a lead of nearly 4,000 points in the ATP rankings and then Murray easily maintain throughout 2017 the top spot in the ATP rankings.
And Djokovic lost will create an opportunity to other players as well. One player I think is Grigor Dimitrov, could take advantage of Djokovic's early exit.
Murray will not only maintain the top spot but he is on a good position to win the AO for the first time. He is now the bettor's favorite to win the AO after 5 finals defeat.