The result will place the new Madrid boss under huge pressure.
Alvaro Arbeloa endured a nightmare debut as Real Madrid coach as Los Blancos suffered a stunning 3-2 loss to second-tier Albacete in the Copa del Rey.
Arbeloa was swiftly appointed by Madrid after Xabi Alonso was relieved of his duties in the wake of their Supercopa de Espana final loss to arch rivals Barcelona.
But a Madrid side that was a long way from full strength suffered humiliation at the hands of a side 17th in the Segunda, as Albacete prevailed thanks to Jefte Bentacor’s sublime 95th-minute winner.
Javi Villar headed Albacete into the lead in the last-16 tie, only for Franco Mastantuono to quickly level.
Bentancor’s far-post finish eight minutes from the end of normal time restored Albacete’s advantage, before it was erased again by Gonzalo Garcia’s 91st-minute header.
Yet there was a final twist in the tale as a long clearance sent Bentancor free down the left channel and into the box. After seeing his first effort blocked, he produced an exquisitely composed follow-up that looped into the far corner to send the Carlos Belmonte into raptures and condemn Arbeloa to a dismal start that will immediately place him under substantial pressure.