The Portugal international believes the Liga giants can still make it to the final as they have learned from their mistakes against Borusssia Dortmund
The Spanish powerhouse were beaten 4-1 at the Signal Iduna Park last week, but the Portugal international remains optimistic about his side's chances of making it to the final at Wembley.
"We have learned lessons from the first leg and we will improve. We didn't start either half well in Germany and kept making the same old mistakes," Pepe told The Times of India.
"We have to believe. It’s complicated, but I still say we can turn the tie around at home. If there is a magic stadium in Europe, then it is the Bernabeu. We have produced so many comebacks in the past and we need that spirit again.
"I think the key to the game is that we score the first goal as early as possible to make them nervous. Three goals in 90 minutes is possible, there is no doubt about it.
"In this game more than ever, we need to be focused right from the very beginning and right to the very end."
Tuesday's match is scheduled to kick off at 20:45CET.