The Spain international was left bewildered by Los Blancos' latest loss at the Santiago Bernabeu to their great rivals, and admitted they now face a difficult task at Camp Nou
Jose Mourinho’s men took an early lead at the Santiago Bernabeu through Cristiano Ronaldo, but the visitors deservedly turned the game around with second-half goals from defenders Carles Puyol and Eric Abidal.
Ramos stated that the team should focus on La Liga now, but refused to give up hope of progression to the next round of Copa del Rey.
"We must be realistic: we didn't do too well," the Spain international is quoted as saying on Real Madrid's official website. "We threw our advantage away and Barcelona were efficient at scoring.
"We must now think about La Liga. It will be difficult to defeat Barcelona at Camp Nou, but we're not about to give Copa [del Rey] away.
"I can't possibly say what we lack to defeat them. You sometimes win and others you lose. It hurts because they are our main rival. It's difficult but not impossible."
Indeed, Ramos feels it imperative that Madrid travel to Catalunya for the second leg next Wednesday still believing that they can progress to the last four.
"Mentality and attitude is what matters," he argued. "We have yet to play the return leg and anything can happen. We must have a winning mentality at the Camp Nou."
The first leg was again marred by unsavoury clashes between the two sets of players, with the lowlight being Pepe’s allegedly deliberate stamp on Barca forward Lionel Messi.
Ramos claims that he did not see that specific incident, but admitted that there had been too much niggle in the game.
"These images tarnish football and they're not worth people's time," the versatile right-back stated.
"Pepe? I haven't seen the images and everything happened very quickly. But our crest should be above all things."
Madrid return to league action away to Athletic Bilbao this weekend, while Barca host Malaga at Camp Nou.
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