With half of the season gone, Barcelona own a five-point lead at the top of La Liga, boast two strikers with as many goals as any other team and look on course for their fourth league title in five years.But how good are they? Six league wins on the bounce has blurred the memory of unrest in September, when problems at the Camp Nou and Santiago Bernabeu appeared almost on an even keel.Coach Ernesto Valverde steered his team back into form while Madrid’s slump plunged deeper, with a change of coach sparking a brief revival, only for old weaknesses to float back to the surface.Real’s troubles have accentuated Barcelona’s superiority, not only in terms of points, where there is a 10-point difference between the club in the table, but on the pitch too.Barca’s 5-1 hammering of Real in October came as a knockout blow for Julen Lopetegui, made even sweeter in Catalonia that they were the ones to deliver it.But more generally, every jolt dealt to Real — by Sevilla, Alaves, Levante, Eibar, Real Sociedad and Villarreal in the league alone — has made Barca’s progress appear all the more smooth.“It is to our advantage but I don’t think too much about the other teams teams,” Valverde said recently. “I never discard anyone, not Madrid nor anyone else.” Barca’s 3-0 win last weekend against Eibar was one of their best of the season and there is a sense now of a team hitting their stride, when rivals were already struggling to keep pace.Philippe Coutinho’s absence from Valverde’s starting line-up had become a concern but against Eibar he returned and was superb.Luis Suarez, who scored twice, is back to his best. Lionel Messi was quiet, but scored his 400th La Liga goal. Perhaps most impressive of all, Barca hardly needed him.Messi and Suarez now have 31 league goals between them while Barcelona’s goal difference is twice as good as that of second-placed Atletico Madrid. The defence, previously creaking, has tightened.