Osasuna are this season the better team in general.
Osasuna are in better form.
Osasuna have lost 2 of their last 10 league games. Against the top two Madrid teams.
Valencia are deservedly in the relegation battle.
Valencia are a mess on and off the pitch as usual.
Valencia miss 6 players due injury, including important ones.
Valencia have won 1 out of their last 10 matches. It was 1-0 v Sociedad by an own goal of Zubeldia.
So scoring has been a problem, they have scored only in 2 other matches in last 10.
Looking at expected points and goals and underlying data Valencia are not as bad team as the results show, but bad run creates bad atmosphere, and an aggressive and confident team like Osasuna is one of the most difficult options at times like these.