I don't sure with Primer League higher level than La Liga will make Barcelona loss compete against Manchester United at playoff round, seem Barcelona more favorite lead to next round than Manchester United based on domestic league achievement by both teams.
MU is not so bad, but I think Barcelona does have a chance to win the game. Even at the European level, it seems that the strategy implemented by Xavi still cannot work over to the European League, seeing that MU is currently in a not good mental condition. Indeed, there is still time for MU to improve their performance and strategy, but in otherside Barce will also improving their performance within this 2 weeks. I think barcelona can manage 1 goal to get 3 points.
No one will confidently say that Manchester United is doing badly in the English Premier League and no one will also say that Barcelona is performing poor in the Laliga. Both teams are doing great in their local leagues and both Xavi and Ten no one among them has proven to be better in the European competitions. Although Xavi has tested it with barcelona both in CL and Europa but was not successful.
This season he failed again in CL, let's see Europa with Manchester United.