Girona advancing to the knock out stage is very possible and they can achieve it but they don seem to have the capacity just yet because they have got a lot to fix to be able to match up the top teams in the champions league that will earn them the opportunity to get the chance at signing at the trophy but getting pass knock out will be a good attempt though it will not be a really easy one as the new champions league format from the group stage is such that is going to be a bit more stressful than the former which they are used to.
No one underestimates Girona now. I also think the same as you, it is possible for Girona to go to the knock-out round. This team has a strong spirit, they are a typical club that want to struggle and do hard work in each match. However, they have a problem with squad quality now because some of the player leave.