Osasuna could be another challenging chapter for Barcelona as sometimes a strong team performs badly against a weaker team, which can be unfortunate for any big team. Barca are playing well at the moment but there are doubts about their chances of winning for sure. Osasuna's position at 14th in the La Liga points table should not be overlooked at all because if the fight on the field favors the weaker team and luck favors them, it is possible to defeat any strong team. Despite Barcelona chances of winning the fans will come together for the result and enjoy the match with it.
You may be worrying too much about Osasuna. Anything can happen on the field, that's the future. But in terms of position and performance, Osasuna is not a big threat to Barcelona. Just because Osasuna has a small chance of winning doesn't mean that Osasuna is going to win the match. I can say for sure that if you were asked to bet on Osasuna, you would definitely refuse, because you yourself know how likely Barcelona is to win. If Barca loses to Osasuna, I would definitely consider it an accident and such an accident is part of the game or a normal occurrence.