The Barça is fourth in League, to 11 points of the Girona (with a party more), the leader, and to 10 of the Madrid. The defeat in front of the Villarreal was a very hard hit to a team that already have escaped him two titles, the Supercopa and the Glass of Rey, and that now only can compete by the Champions, since the possibility to win the League is almost a miracle.
Any team has been able to trace back this distance of points, but yes there is a club that has achieved to win a league with 9 points of advantage of the leader: the Barça. In the season 1998-1999, the Barcelona group, trained then by Louis Go Gaal and José Mourinho, attained the exploit to trace back a League that seemed won by the Mallorca, that took him out 9 points.
To the Real Madrid traced him back eight points
Sucedió In the season 2003-2004. The Real Madrid of Carlos Queiroz left trace back by Valencia when it seemed that it went it to win after taking out him 8 points. A League that finish losing after a second stretch of the horrible season. In fact, it finish falling in the fourth position by behind Valencia, Barça and Sportive of the Coruña.
In the season 2014-2015, the Barça of Luis Enrique heaved with the trophy of League after tracing back him to the Real Madrid a distance of 4 points. It recovered the leadership in the day 26 and proclaimed champion in the last party of the championship in front of the Athletic of Madrid in Vicente Calderón with goal of Leo Messi.