I doubt Sasuke will ever be able to beat Itachi.
As he himself said...`Why is there so big a difference?` or something along those lines. Kakashi can beat the crap out of Sasuke without breaking a sweat, and Itachi can pretty much hammer Kakashi, (probabaly getting wounded in the process). So Sasuke really isnt anywhere near his level...hes faaar, far away. Not to mention if he keeps pulling stupid stunts like going to Oro, etc...hes just slowing his progress down in the long term. Another thing, even if hes amazingly more powerful as time goes by, Itachi is ALSO improving, so he mantains a constant and huge gap in power.