Barcelona ended a decade-long drought without winning away to Real Sociedad on Thursday as Neymar's first-half penalty handed the Spanish champions a 1-0 Copa del Rey quarter-final, first leg lead.

Barcelona striker Luis Suarez insists the Catalans are "obliged" to chase down Real Madrid at the top of La Liga, despite losing more ground on the European champions in a 1-1 draw at Villarreal on Sunday.