By ESPNSTAR.com staff
Goals from Lucas Vazquez, Denis, Esteban Granero and a brace from Angel Di María ensured that Real didn't need to break a sweat in the start of their pre-season friendly fixtures.
Karanka saw nine players from the Castilla team take part and demolish the Segunda Division B side in the game. Despite the club boasting a number of stars, he believes it was important for the youngsters to have a chance to shine and demonstrate their progress for the senior coaching staff to assess.
The Real assistant manager was impressed with what he saw even as he reiterated that friendly results do not necessarily point towards the strength of the side ahead of the new season.
The Castilla has developed a number of notable players, many of whom have gone on to play for other major European sides. The academy's graduates include the likes of Esteban Cambiasso, Santiago Canizares, Guti, Juan Mata, Roberto Soldado as well as first-team regulars Alvaro Arbeloa and Iker Casillas.
"Real Madrid's youth academy is very good and it has been the same for a long while. We have always trusted in it but these players have to complete their progression through the ranks," Karanka noted after the match.
"We need to keep building on working [on cohesion] until the whole team can be together in the USA. It is important to score goals but best thing in these games is to build-up pre-season pitch time."
Granero was appointed as the captain for the game and stated his pride at getting to be the first person to don the armband for the new season. And he was equally pleased with the display provided by the many teenagers who are vying for a first-team spot in the future.
"It is a pride to be captain of Real Madrid although it was a pre-season match," he said.
"The guys from Castilla are helping a lot and are proving they can contribute well.
"I try to help them with everything that they ask of me."
The youth set-up will play in the Segunda Division and only recently celebrated success in tandem with the senior squad's La Liga win as they were promoted from Segunda Division B in comfortable fashion.
Real will next play Benfica on Friday before heading to the United States where they will play Los Angeles Galaxy, Santos Laguna, Celtic and AC Milan in the 2012 World Football Challenge.