New Spain head coach Julen Lopetegui says it is critical they stop living in the past if they are to regain their place at the top of world football.

After establishing an era of dominance at international level, in which they won the World Cup in 2010 and back-to-back European Championships in 2008 and 2012, Spain have endured a decline in recent years.

A humbling group-stage exit at the World Cup in Brazil two years ago was followed by a last-16 defeat at Euro 2012 at the hands of Italy, after which head coach Vicente del Bosque stepped down from his role.

Lopetegui, who coached Spain's Under-19 and Under-21 teams to European Championship glory in 2012 and 2013 respectively, believes now is the time to focus on introducing younger stars into the senior side as they prepare for their World Cup qualifying campaign, which begins against Liechtenstein on September 5.

"Spain have been dominating world football for a decade, and now two championships have come along, a World Cup and a Euros, where we haven't done that," he told AS.

"This is the reality, and what we now have to face during qualifying for Russia 2018, which will be very tough.

"But we have to put all our energy into doing well in the things that are under our control. We're aware of the difficulty of qualification, but also the capability of the Spain team and its potential.

"You need constant renewal. Spain has had the best generation in its history, but [Carles] Puyol, Xavi are no longer there. You can't live in the past.

"Now I want to mix the best of several generations."

Lopetegui will not rule out a call-up for any eligible players, but suggested that Atletico Madrid's Saul Niguez, Barcelona's Denis Suarez and Marcos Asensio of Real Madrid are three young stars who could be key to his plans.

"Logically, Saul, Denis and Asensio are in our thoughts," he said. "They have a profile that fits the style I want Spain to have.

"I've looked at a number of players who have potential and we have to control them. I don't want to close any door to anyone."