On paper, Barcelona is indeed more favored than Inter Milan, but that is only a calculation on paper and what happened was different from what was predicted, Inter Milan actually showed they were ready to compete.
Even if Barcelona is the favorite team and people say they are stronger, there is no guarantee that they will beat Inter Milan. In fact, Inter Milan almost defeated them in the first Leg. Since Inter Milan could get a draw result in Barcelona home, I think Inter Milan has a bigger chance in the second Leg because it will be in Inter Milan home. Inter Milan know better their home stadium, it will be advantage for Inter Milan. and Inter Milan also has more motivation because they are playing in front of their home base fans/supporters. I favor Inter Milan to win the next match.
In fact, in this case, I think Inter Milan is more advantaged, because when they are not made the favorites of many people, then morally there is no pressure that burdens them, on the contrary it can be a motivation for them to show their quality.
Well, in the first leg they have done that, we just have to see whether they will be able to do the same thing again in the second leg or not, they should be able to show it because they will be playing at home too.