After 4 consecutive league games without a win, Barcelona finally delivered. Maybe Valencia was not the strongest rival (19th place currently) but 7-1 was still very impressing.
Right now Barca has the best attack in the league with 59 goals scored, which averages to over 2.8 goals per game. Unfortunately for them, it's the points that counts, not goals. Points-wise they're still 7 behind Real, as Real didn't have any problems defeating Valladolid (3-0), so I have very little hope for them to stop Real from defending their title.
It's true that points are the main thing that determines a team's position in the table and of course, a seven-point gap is a big gap and it's difficult for Barcelona to overtake Real Madrid. Unless, for example, Real Madrid is not a top team that has great dominance, then maybe such a gap can still make Barcelona overtake it. But yes, the reality is that Real Madrid is a team with good dominance and also has a great winning mentality, thus it is difficult for Barcelona to overtake Real Madrid.
Because anyway, the only way Barcelona can overtake Real Madrid is by hoping for Real Madrid's inconsistency by having several consecutive defeats. But unfortunately, when Real Madrid are already at the top of the table for the second half of the season, overtaking Real Madrid will certainly be a difficult target.