It's all about the draw. We have to avoid Bayern, Real Madrid, Barcelona, and Chelsea, at least until the final.
Ideally, 2 of them will get paired in the next round. Maybe PSG will even do us a favour against Chelsea. The other 3 will definitely all qualify though.
If we can get Basle/Porto in the next round, then we're favourites to qualify for the Semi. Even a draw against Juve/Dortmund or Leverkusen/Atletico could be navigated.
Look at Porto's run in 2004. They played man United, Lyon, Deportivo, and Monaco.
They let Deportivo take out Milan, and Monaco take out Real Madrid, two of the favourites that year, and beat those two themselves.
We need similar luck and efficiency to go far.