Barcelona is currently not showing the best of performances. Because Barcelona has drawn the first match after the break. That was the match Barcelona really should have not drawn.
We also very well know, that Barcelona has some problems going on with the team. The team itself is not a very balanced one. You know, they are also unable to bring in any new players, any new good players right now in the team. Thats obviously because of the financial problems they are facing right now.
Another thing is Barcelona right now is concentrating more on the La Liga title. So, I am not very confident about winning against Manchester United. Manchester United on the other hand has shown some significant improvements.
Duke Khan
Barcelona's only chance is that United will treat the Europa League as their second priority this season. There are all prerequisites for this - United are doing well in the Premier League and they have every chance of not only gaining a foothold in the top 4 but even climbing higher. Given the value of qualifying for the Champions League, this looks like a bigger deal than beating Barcelona. Winning the Europa League also gives a direct ticket to the Champions League but it is less "guaranteed" as there is a lot of randomness in the knockout games.
I don't think Manchester United will be treating the Europa League as their second priority as you just said. Manchester United has stepped up their form a bit and is putting in more consistency in its winning, but I will not be fast to say that they will be able to overthrow Manchester city not to talk more of Arsenal who seems unyielding and indomitable this season. For that, man united will be more focused on the Europa League than The EPL. The only problem is that they will still have to defeat Arsenal before they could secure the Europa title. For now, I see Arsenal as man united greatest Rival.