Yes you are right barcelona is far away from real madrid they can't catch them. The points gap are too huge even if real madrid have failed to win against Atlatico Madrid, Still there will be a difference of 7 points between these two rivals, Even let suppose if real madrid loses back to back matches, then still I believe barcelona can't stop them from winning current season league and that's why Real Madrid is a strong candidate to win La Liga this season. Barcelona could not hold the 1st place at early stage of the season due to thier instability although their attack are too good at this season. By the way compared to league barcelona is performing well in UCL, so that's why maybe barcelona will win UCL. But there is still plenty of time left to be UCL dominater, while la liga has already been claimed by madrid.
Barcelona have become almost impossible to beat Real Madrid now, although they have been performing well recently, but they are currently in this position due to some bad performances in the middle. Where I thought Barcelona would be the second option if they were not at the top of the points table, but Atletico Madrid has taken that place.
The gap that exists now is that it will only be possible to beat Real Madrid and Atletico Madrid if they lose their upcoming matches, but I don't think they will lose to those weak teams.
Anyway, leaving aside these discussions, if we talk about today's match, then the first half of the match between Leganes and Rayo Vallecano has already ended. Neither team has been able to score, but Rayo Vallecano has held the match position more according to their strength. I think they will win this match even then the score will be 1-0.