The Catalans' transfer chief is adamant that the club will succeed this season despite having failed to bolster their defensive options this summer Barcelona sporting director Andoni Zubizarreta has defended the lack of a centre-back signing this summer and says the squad is strong enough to succeed as it is. While the Liga champions were able to bring in Neymar from Santos, they failed to sign a centre-back, leaving head coach Gerardo Martino with Carles Puyol, Gerard Pique and Marc Bartra as the obvious centre-backs available, though Alex Song and Javier Mascherano have featured in defence at times. The Catalans were linked with the likes of Paris Saint-Germain's Thiago Silva, Marquinhos (who joined PSG from Roma instead) and Chelsea's David Luiz but failed to agree a transfer with any clubs, but Zubizarreta is content with Barca's summer transfer activity. "In the history of Barcelona, the signing of a centre-back has always been complicated," he explained. "We have the squad we wanted and one that will be able to compete extraordinarily well. "We are always focused on making the squad the best it can be and I am delighted to have the chance to do my job." Barcelona conceded their first goals of the league campaign on Sunday in a 3-2 win over Valencia, with skipper Puyol nearing a return from a knee injury.