Hmmm that point was actually sort of a fail from Feds. Walks around for the forehand but hits it almost right in Djokovic's strike zone. Fed goes "Oh shit" like 95% of players to when they leave almost the entire court open like that and immediately starts the run.
Had Djokovic hit a simple shot behind Feds instead he'd probably wrongfooted him and even if Feds miracously got his racket on it he'd have a much harder backhand volley.
On the other hand Dimitrovs "epic point" is actually a similar mistake but Troicki is smarter than Djokovic and forces a much harder volley. Still somehow Dimitrov makes it