if madara has rinnegan he wins without difficulty.
if not it'll be a close one
if neither sasuke nor itachi could take control of kyuubi madara wins in a close one. if the brothers can take control of kyuubi they win with mid effort
itachi will simple seal him away with that sword and the fox well not that much of a problem sasuke can now control it he has got ems either madara wastes time trying to gain control of the fox and bang itachi will seal him or he fights itachi and sasuke gain control of the fox and tells him to use tailed beast bomb and madara dead
Madara hands down, will be a good fight though and we'll get to see itachi be completely serious, no two opponents can let their guard down against madara.
Itachi and Sasuke would win, most likely barely. Their Sasunoo's are way better than Madara's. Plus 2 super strong ninjas can most likely take out 1 super duper strong ninja
Madara with difficulty
lets remeber that he has the rinnegan
which is; as said in the manga;
something you obtain when you reach the highest level of sharingan
so if you think about it like that
Madara's eyes are better
annd he also has the nine tails
all that chakra
but itachi is extremely intelligent and would put up a good fight