Barcelona is indeed performing very well and is currently ranked 1st in the standings and even though some time ago he was in the lower rankings because there were times when Barcelona did not play consistently to win but finally they were able to regain a good position in the standings.
After the international break, Barcelona will play 2 matches this week. I think that's a big deal for Flick. Many Barcelona players play for the country. I think there is a considerable fatigue.
But in other positions, Osasuna is also not in the best condition. Osasuan is winless in the last five matches in La Liga (three draws and two losses). It's hard to predict, but if Barcelona are all in good shape, then I'm sure Barcelona can win. Barcelona must be able to get 3 points, so that they are more comfortable in 1st place and have a difference of 3 points with Madrid.