Things are going quite well for Barcelona in the La Liga. Of course being eliminated in the Champions League is a big disappointment for them. But I don't expect this to affect their performance against Valencia too badly. They destroyed Valencia by 4-1 in their last head-to-head game as well. We might watch a similar game here.
Valencia game against Barcelona is supposed to be an easy win for Barcelona considering Barcelona's form in the League and the poor form of Valencia since the beginning of the season but Valencia not getting a win in three matches in Laliga and Barcelona losing out in the Champions League can affect the performance of the two teams negatively or positively, for Valencia, they haven't defeated FC Barcelona recentlyly going with their history but playing at home in front of their fans who are hungry to see them win could add to the moral of the players to make things so difficult for Barcelona who was trashed 0:3 by Bayern Munich in their last Champions League match.
For FC Barcelona, I think they will capitalize on the poor form of Valencia to continue their decent performance in the Laliga since they still have the hope of getting back to the top of the League if Real Madrid get defeated by their opponents Girona or Barcelona may probably close the 3 points gap between them to keep their title hope alive so is going to be a big clash for the team with Valencia hoping to get their first win after several matches in Laliga and also defeating Barcelona after a long time.