If you think Real Madrid's current form has dropped, then how do you really believe they can beat Barcelona at Camp Nou for the second leg?
You could say Real Madrid has a chance of qualifying for the Copa Del Rey final by beating Barcelona, but don't say it's an easy job. After all, there is no guarantee that Real Madrid can play their best players without injury, that's because the second leg will be played in April.
Real Madrid dominated a lot and created chances, but they couldn't get a single shot on target, which seems to be the merit of Barcelona's defense. While Barcelona took one of the few opportunities and scored a goal. The result does not match the game, but this sometimes happens. Real Madrid should have at least not lost at home, now the away game will be even more difficult, and now they definitely need to score.