The Spanish giants are tied at 1-1 after the first leg at the Bernabeu in which 19-year old Raphael Varane cancelled out Cesc Fabregas's opener for Barcelona.

Pepe believes French centre back Varane can become one of the best defenders in the world.

"He (Varane) is a really down to earth guy with tremendous quality," the Portugal international said.

"At beginning of the season I said that within two years he is going to be one of the best central defenders in the world. He has helped us a lot in games and can get even better.

Looking ahead to Tuesday's return leg at Camp Nou, Pepe called on his side to show unity against the formidable Catalans.

"We have to play as a team, like we always try to do in every game," he said.

"If we play as a team we'll definitely have a great chance of getting through the round.

"As I've said before the chances we have involve playing as a team. We have to be faithful to our style of play and do everything the manager asks of us.

Pepe struggled to pick a winner from the other Copa del Rey semi-final tie, which Atletico Madrid lead 2-1 from Sevilla.

"I think that this match will be decided by details as Sevilla and Atletico are two very good sides," Pepe said.

"May the best team win and meet Madrid in the final."