Villarreal goalkeeper Sergio Asenjo and Espanyol number one Kiko Casilla believe their national teammate David De Gea would fit in perfectly at Real Madrid should the Manchester United star decide to move to the Santiago Benabeu in the summer.

Asenjo and Casilla have been back-up choices for Spain manager Vicente Del Bosque, behind De Gea and Iker Casillas, replacing Victor Valdes and former Liverpool star Pepe Reina due to their lack of playing time at Old Trafford and Bayern Munich respectively.

The Villarreal and Espanyol 'keepers believe De Gea has the potential to thrive at the Santiago Bernabeu and say he would have a healthy battle relationship with Casillas for the role between the sticks, like they do for Spain, where the Real Madrid stopper remains as the number one.

"All the good goalkeepers fit everywhere and David is a good one. He is not just a promising star but already world class. He is proving how good he is [at Manchester United] and I wish things go well for him," Asenjo said to Marca.

De Gea has been tipped to replace Casillas at Real Madrid since the start of the season, with the veteran 'keeper expected to leave the Champions League holders in the summer after falling out of favour with his own fans.

But recent reports suggest Casillas will stay until his contracts expires in summer 2017, meaning he will have to battle De Gea for the jersey if the United star joins Los Blancos.

Some have suggested De Gea would rather to see Casillas leave to avoid any competition, while he wants assurance of being the main choice like he is at Old Trafford. But Asenjo and Casilla claim the duo would manage to adapt if they ended up competing at Real Madrid.

"When I have been with Casillas and De Gea in the national team their relationship is good. There are good vibes with [Spain's goalkeeper coach] Ochotorena and also with me. There is a good harmony there, I don't now what will happen in the future [should De Gea will join Real Madrid] but in the national team there is a good atmosphere," Casilla said.

"Iker and David are two really good goalkeepers, two of the best in the world, and they are proving it. I don't know who is better but both are really good."