It's surprisingly simple. Madara has Sharingan. One of its abilities is predicting or foreseeing any sort of movements. That's how Kakashi copied Zabuza's Water Dragon remember?
Also combined with Sennin Mode, this ability along with his natural reflexes is enhanced drastically.
For reference sake, Naruto was able to dodge the 3rd Raikage's Jutsu (Which is really fast) with Sage Mode.
Ironically in the same scenario, Sasuke was able to dodge Ay's punch to counter with Chidori, thanks to Sharingan.
So my point is that both Sage Mode and Sharingan gives the user enhanced reflexes. Combine them you are virtually impossible to touch.
Also combined with Sennin Mode, this ability along with his natural reflexes is enhanced drastically.
For reference sake, Naruto was able to dodge the 3rd Raikage's Jutsu (Which is really fast) with Sage Mode.
Ironically in the same scenario, Sasuke was able to dodge Ay's punch to counter with Chidori, thanks to Sharingan.
So my point is that both Sage Mode and Sharingan gives the user enhanced reflexes. Combine them you are virtually impossible to touch.