Inter have a weak defence this season, conceding 9 goals in 7 games. In comparison, they conceded 22 goals in the whole of last season. So theoretically Roma have a choice of how to play, maybe an aggressive game with an emphasis on attack will be a surprise for Inter and they won’t be able to find an answer, who knows. But as I wrote earlier, it looks like this game will end with Inter winning 2-1.
I don't think it is as a result of a weak defense that inter Milan have conceded much goals this season because if you had noticed then you would have seen the circumstances that led to them conceding those goal. It is normal for teams to concede goals because some of these teams they may face some teams with good scoring abilities and at such conceding goals could be inevitable due to the nature of the team they are up against but the most important thing is for them to keep winning and then try to reduce the deficit.
Are you serious? Ok, I looked at the goals Inter conceded: 2 goals from Genoa, 1 goal from Monza, 2 from Milan, 2 from Udinese, 2 from Torino and two more games without conceding a goal. Do you think that 7 games is not enough of a sample to draw conclusions and they were "just unlucky" 9 times? Please note that all but Milan here are pretty mediocre teams. You are probably either a big optimist or an Inter fan.