Inter - Barcelona will be eyed very closely indeed. Inter aren't having good days recently. They have defensive and offensive issues both now. They have another difficult match against Roma before facing Barcelona in the Champions League. If they don't have a good result against Roma too it would demoralize them even more. In any case it isn't easy for them to recover magically in a short time though.
Barcelona have had a very impressive run so far. Maybe they lost to Bayern Munich here but their performance was still decent. Their performance in the La Liga has already been very satisfying. I expect them to show the same performance against Inter too and have the control of the match. They can win this to make up for the Bayern Munich loss.
Yes Inzaghi's troops are not in great shape. especially in the last match, Inter had to lose when they played away games at home to Udinese. after the international break, Inter will play host to Roma, Inzaghi must fix his squad, especially in their defense line which is quite fragile.
as you said, it is not easy for them to miraculously recover in a short period of time.
As for Barcelona, I don't see Barcelona playing badly when they travel to Bayern.
I think they were just out of luck at the time. In this match, Barcelona should be able to beat Inter easily. three points, is a mandatory result for Xavi Hernandez's squad.