The days after Xavi, Iniesta, David Villa and Fernando Torres would always be an uncertain transition period for Spain. When their golden generation hung up their boots one by one, they have been desperately struggling to live up to their former glories since they were last crowned European champions in 2012. Amazingly, on their way into their Euro 2020 collision with Croatia, they had not won a knockout game in a major tournament ever since Italy conquered Kiev eight years ago. But slowly it begins to feel like the cavalry…