Barcelona cruise into Copa del Rey last 16
Barcelona's Brazilian forward Neymar looks on during the Spanish Copa del Rey (King's Cup) FC Barcelona vs FC Cartagena finals stage match at the Camp Nou stadium in Barcelona on December 17, 2013
Cartagena threatened to embarrass their illustrous hosts when Zurdo struck the post midway through the first-half.
However, any hopes the visitors had of a famous victory were quashed when Pedro neatly swept home Martin Montoya's cross for his third goal of the tie.
Without a host of regular starters, Barca struggled to create clear-cut openings all evening but they were gifted a second goal 23 minutes from time when Mariano Martinez turned Cristian Tello's cross into his own net.
And Neymar rounded off the scoring with his sixth goal in his last three games when he headed home Andres Iniesta's cross three minutes from time.
Barca will now face Getafe in the last 16 after the Madrid side thrashed Girona 4-1 to secure their place in the next round by the same score on aggregate.
Osasuna, fresh from their 2-2 draw against Real Madrid on Saturday, will face Los Blancos again in January should Madrid overcome Olimpic Xativa on Wednesday as the Navarrans progressed on away goals after a 1-1 draw at home to Malaga on Tuesday.
Meanwhile, Levante beat second division Recreativo Huelva 4-0 to also progress 4-1 on aggregate.