Barcelona held on with 10 men for the last half hour as Raphinha's goal gave them a 1-0 victory over second-bottom Valencia.
The former Leeds man made a diagonal run from the right flank to meet Sergio Busquets' perfect clipped ball over the defence with a header to put the hosts ahead on the 15-minute mark.
Ad Sloppy defending from Marc-Andre ter Stegen and Andreas Christensen gave opportunities to equalise for Samuel Lino and Ilaix Moriba before the break but both spurned the chances.
Copa del ReyMilitao own goal gives Barcelona the advantage in fiery Copa del Rey semi-final02/03/2023 AT 19:31 Eight minutes into the second half the game should have been put beyond doubt but, after Jules Kounde's effort was blocked by Hugo Guillamon's arm, Ferran Torres' spot kick clipped the outside of Giorgi Mamardashvili's right-hand post.