It is legendary now that when the Spanish national team was coming to the boil and about to scald world football for six years, La Roja's own fans didn't even know the water was hot. Because they left Spanish soil having eked out two single-goal wins, over Peru and the USA, the booing, whistling and jeering which had pursued them around the peninsula for two years was the last thing they heard before heading off to win Euro 2008. Three trophies later, the senior team is finally in search of a reboot. The identity has been eroded by the passage of time. The transition from excellent to elderly is never fun. Spain lift the trophy at Euro 2008, but their fans had booed them before, not recognising a great team . The World Cup followed in 2010 and now it seems the right time for the old guard to hand over to youngsters . Spain won the European Championships for a second time in a row in 2012 before their World Cup failure . Spain's Under 21s celebrate winning Euro 2013 and their brilliant young players are thriving right now . Nevertheless, the current Champions League quarter-finals are beginning to say something quite interesting about Spain's 'relevo'. If you don't speak Spanish, that term might mean very little to you. But I bet you can intuit. 'Relevo' in this context is like 'relief' — as in the armed forces term for the relief watch. Those who are sent in, fresh and ready, to relieve whichever servicemen or women who have born the brunt of service for the previous day or days. Xavi, Carles Puyol, Xabi Alonso, Carlos Marchena and Joan Capdevila have done their hard miles and it is not clear what toll battle has taken on Victor Valdes, David Villa and Fernando Torres. The natural place to look for fresh, young, well-drilled recruits ready to take on the world is in the Academy graduates. So let's go there. What caught my attention is that Juan Bernat's arrival to the Champions League quarter-final for Bayern Munich at Porto last Wednesday earned Valencia a seven-figure sum as part of the incentives associated with the full back's move to Bavaria. In other words, Bernat was one of those guys, just turned 22, that both Valencia and Bayern thought might be playing 'starting' football at this elite stage of the world's most demanding soccer tournament — but, equally, he might not. The likes of Xavi (right), Barcelona's midfield metronome, have done their hard miles and can now hand over . it is not clear what toll battle has taken on striker Fernando Torres, who now plays for Atletico Madrid . This is the season when he's broken into Vicente del Bosque's senior team, scoring, and formed part of a quite remarkable chain of left backs at the Mestalla — from Jordi Alba, European Champion with Spain in 2012, now at Barcelona, through Bernat to Jose Luis Gaya, a remarkable talent who is currently locked in stalled contract talks at Valencia while Madrid stalk his availability. And if you just look a little more closely then the eight teams left to sort the wheat from the chaff this week show evidence that, beyond Bernat, Spain still have a golden harvest to bring in. For example, take a snapshot of the penultimate trophy Spain won — not Euro 2012 but Under 21 Euro 2013, beating Italy 4-2. In that final they lined up: David de Gea; Martin Montoya, Inigo Martinez, Marc Bartra, Alberto Moreno; Koke, Thiago, Asier Illarramendi; Cristian Tello, Álvaro Morata, Isco. Juan Bernat (right) played in the Champions League  and is the latest in a string of thriving Spaniards . David de Gea (right) has been in fine form for Manchester United and is a real goalkeeping talent for Spain . Of Spain U21's starting line-up at the 2013 Euros, only De Gea hasn't played UEFA football this season . Of that starting line-up only De Gea hasn't played UEFA football this season, eight of them are still in the Champions League quarter-finals while two of the substitutes, Nacho and Dani Carvajal have decent minutes in the competition. Throw in the fact that Spain's winning Under 21s coach was Julen Lopetegui, 3-1 up on Pep Guardiola's Bayern going into the second leg this week, and the progression from youth-level international football to full-fledged senior winner is going along very nicely. The eight starters and two substitutes from that 4-2 win are all now in the age range of 23 to just having turned 25. Between them they have 184 appearances in UEFA club matches — the vast majority of which are in the Champions League. Koke has played in the Final, Isco, Morata, Carvajal, Nacho and Illarramendi have won it, while Bartra and Thiago have played in a winning campaign. And it is important to throw in the fact that in last week's quarters, 20-year-old Oliver Torres (13 UEFA club matches) stood out against Bayern for Porto (he belongs to Atlético), while on the bench for the Madrid derby were fellow 20-year-olds Jese and Saul Nguez, who have 18 UEFA appearances between them. Spanish fans didn't quite know the great team they were getting in 2008, they could have another one now . Alvaro Morata (right) celebrates with team-mates after scoring against Germany at Euro 2013 in Israel . Whether they flower for club and country or bloom early but fail to excel like recent Spanish generations have proven to do, the fact remains that there is a wave of fresh, exciting Spanish talents who demand attention now. This week in fact. Lopetegui, whose result probably constitutes one of the performances of the season, has a firm view. 'I don't think there's strictly a "Spanish school" of coaching or playing,' he argued earlier this season. 'There's just "training" and "playing". So what I' ve always looked for are kids who know how to understand the game. I think it's a common misconception that players completely understand football and how it's played. Former Under 21 coach Julen Lopetegui has managed Porto to one of the results of the season in midweek . 'Understanding precisely what's going on in a game is not at all easy. 'The key is knowing what to do with the ball so that you don't lose possession and get caught disorganised. Never gift away space to an opponent. 'When you control the ball and space on the pitch, then you must know how to take advantage. But the line is thin, you want to make the players effective and efficient but never to kill off their creativity and capacity for invention.'
When Spain first became a real power, their own fans didn't know at first .
The European champions won three trophies on the spin, but need a reboot .
Likes of Xavi, Carles Puyol, David Villa and Fernando Torres can hand over .
Juan Bernat's Champions League performance signalled part of the new era .
Spain still have a golden harvest to bring in from the country's youth .
Former Under 21 coach Julen Lopetegui downed Bayern Munich this week .
Almost all of their former youth side are playing in European competitions .