Real Madrid's next game will be against Leganes, which is an easy game for Real Madrid, and they will definitely win this game and will be level with Barcelona on 63 points, but Barca's greater goal difference will keep them at the top of the table unless Real scores 19 goals in this game.

Real Madrid is struggling to score many goals as they used to do. It depends of course but I find them in the previous years way better than this.
Do not forget also that Real Madrid will play one game more than Barcelona once they defeat Leganes, so theoretically will remain 3 points behind of them.
Carlo Ancelotti is aware of his team problems but didn't figure out how to run his players/machine effectively.
If the outcome of a match is random then this equation can easily be changed. Barcelona knows that the difference of 3 points is not a big difference at all, that's why they don't want to make mistakes in any match. If in any match Barcelona makes a mistake and Real Madrid does well, then Barcelona will fall behind and Real Madrid will once again go to the top of the points table. The competition in this league is going to be tough and whichever team Barcelona Real Madrid or Atlético Madrid wins the title will ultimately compete hard and then win the title.