However, the result also eased the pressure on Jose Mourinho and his assistant insisted after the game that they had showed they were on the road to improvement after a poor start to the campaign.
“During this season Mourinho has explained several times that we are trying to improve,” Karanka said.
“Everything we do is to improve and it seems that we are on a good path. We have to continue this way.”
He added: “In Valencia we showed what we can do. Now, the cup will be totally different. Wednesday will be different and the fans in the Mestalla will be even more with their team.
“Our mission is to bring us closer to what we did last year [in winning La Liga].”