Djokovic would have won 3 in a row. That is his biggest edge over Agassi and Federer who werent able to do that. ****s claim Federer is better than Sampras at the U.S Open because he won 5 in a row even though Sampras has multiple more finals, more semis, won his titles over an incredible 12 year stretch. That he spanked Federer so decisively twice there is just an added reason to favor him with both winning 4 though. You can moan about post prime Federer all you want, but those matches were January 08 and January 2011, Federer was 26 and 29 so not even in his 30s, and Federer was winning slams up until 2012 (atleast) and was the #1 or #2 seed in both and got crushed both times by the lower seeded and ranked Djokovic, who btw was only 20 at the time of crushing a 26 year old Federer. Had it not been for the mono excuse nobody would say Federer wasnt much more in his prime in Janaury 08 than Djokovic for that matter. Now to compare this with a match against a 35 year old Agassi already a couple years past his final ever slam is simply ridiculous, but to be expected from ****s, who have long acted like Federer's 8-3 record vs a 32-35 year old Agassi is one of the all time most incredible stats and proof of his undisputed GOATness, LOL! If it will provide you with comfort I wont reference a match of a 35 year old Federer ranked 8th in the World vs anyone at any event if it comes to that.
As for Agassi, he has won 4 of his 9 career Australian Opens, an incredible stat, especialy given that 5 of the ones he played he was 30 or older.