AS Roma only needs a draw in the second leg to ensure they truly deserve to be contenders for the Europa League title. In my opinion, AS Roma journey to win the trophy will be much easier if their strength is ignored by other contestants, they can create surprises in every match. Claudio Ranieri once created a miracle with Leicester, perhaps that history will repeat itself. If AS Roma manages to lift the trophy, Claudio Ranieri will truly be a legendary manager who won a trophy in a unique way, as Jose Mourinho once said.
Based on the Odds displayed for the second leg match, AS Roma strength is indeed not so calculated, where Athletic Bilbao looks very favored, we realize that they will play in front of their own supporters. AS Roma must work harder than ever to be able to realize their dream of winning the trophy, or at least reaching the quarter-finals.
You're right, AS Roma just have to hold Atletico Bilbao to a full time draw win the match but it's risky since they'll be visiting Bilbao's home for the second leg, that's a hedge to Bilbao since it's their ground and they'll play better to impress their fans. Moreover them on the other hand still got chances of qualifying they can score one goal and play extra 30 minutes that could lead to a penalty and luckily suprise everyone by qualifying through penalties to the next round, there Roma should just go over there to hope for a full time draw they should try score more goal to boost their chances of qualifying thereby making it more difficult for Bilbao. Anyways their recent form is impressive if you go through Rom's stats you'll see how well they've been performing recently, they're yet to be defeated in their last five fixtures hopefully they'll maintain it against Bilbao when they travel to Spain.