Congratulations to Stan Wawrinka! He once again proved that he is a nemesis to Djokovic (at slams) and when he is ON, he is very tough to beat at a Slam.
As for Djokovic, all the physical nagging injuries finally caught up to him at the final. Also, he became Federer at this year's US Open final with an abysmal 3 for 17 (18%) on break points conversion. Finally, he only served 51% for the whole match so there was something wrong with his shoulder.
Here's an interesting stat: Djokovic has 5 losses in slams after winning the 1st set. 4 of those losses came since 2014. And here's another interesting stat: 3 of those losses were against Wawrinka (2014 AO, 2015 RG, and 2016 US Open) and 3 of those losses happened in the final (2014 RG, 2015 RG, and 2016 US Open).