Barcelona needs to try their best in order for them to win Osasuna, otherwise, they'll have to fight till the end of the season on pressure to make sure Madrid does not take over them. I feel this is the best opportunity for Barcelona to widen the point gap, because we don't know the unforeseen challenges that might come up in future before the end of the season. It's an important match for Barcelona.
What will happen on the field is completely unpredictable. Considering the statistics and form, Barcelona has a much higher chance of winning than Osasuna. I think Osasuna can pose a big threat to Barcelona in tomorrow's match. Barcelona will not want to lose this match at all. Because, this is the only chance to increase the gap with Real Madrid. If they cannot get 3 points against Osasuna, then they will have to continue the fight with Real Madrid again with 60 points jointly. They definitely do not want to lose or draw this match, they need the full 3 points to increase the gap with Real Madrid.