Honestly, when Barcelona works hard enough, they will be able to beat Real Madrid, but for now I think they shouldn't have too many illusions about winning the League, yes, they are winning the League, it's because Real Madrid has allowed them to, and for now Real Madrid things are going very well in the UCL, which is something very big, for now the League is something that Real Madrid can once again take first place in the table, Barcelona have to focus more of their energies on the Europa League to see if they enter back to the UCL season, but they have it very strong because Man United, despite the fact that their spirits are very low because of CR7, I think they can come to play with everything.
Man United want to get back to the UCL no matter what, and the only thing on their mind is to have a lot of wins, this is where they need to focus a lot more.
I do not think that Real Madrid really "allowed" anyone to be the first, they are playing well, they haven't lost or got a tie that commonly, they are playing well, the difference is that Barcelona is playing even better.
This is why I believe that we are going to end up seeing Barcelona win the title this year. On the other hand, if Barcelona still goes on to finals and win Europa cup, while Real Madrid somehow manages to lose both domestic cup and UCL at the same time, then we are going to see Real focus only to league, while Barcelona focusing on many other competitions and there could be some trouble there for sure, which will create a trouble for them.
It sounds very funny for you to think that Real Madrid allowed Barcelona be at point where they are now. That's not, you just give excuse. Real Madrid can't allow or give Barcelona the chance to win because they are all fighting to win the league, if Barcelona ate doing well and ahead it doesn't mean because Real Madrid allow them.