Germany head coach Joachim Low has been stunned by World Cup rivals Spain's descent into chaos after Julen Lopetegui's departure on the eve of Russia 2018.

It was confirmed on Tuesday that Lopetegui would take over at Real Madrid once the tournament had come to a conclusion - news that came as a surprise to many.

Moreover,  in a sensational development 24 hours later, Spain announced that Lopetegui had been sacked, with Fernando Hierro set to take over the reins for the finals.

READ: Spain sack Lopetegui and other World Cup implosions

Hierro's first task is a daunting one - a crunch Group B meeting with Portugal on Friday - and Germany boss Low conceded the whole saga had come as an almighty shock.

"I was also surprised and it very much came out of the blue," he told the media, ahead of the defending champions' opening Group F encounter with Mexico on Sunday.

"I've no idea about the background of the Spanish Federation's decision. To put it mildly, it is very unusual, if not a total bombshell."

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"Let's not beat about the bush - it will lead to difficulties and a bit of unrest. Fernando Hierro has experience in coaching and I think he was assistant coach for Real Madrid for a while. He went to Valencia and was head of sporting affairs, but I cannot evaluate his qualities as a coach."

"However, Spain has been together for years and years. They have a clear philosophy. Just look at Barcelona and Real Madrid, who leave their mark on the national team."

"The players know each other well and have done for many years, so at the end of day, Lopetegui or no Lopetegui, Spain will not lose any of their class or quality."