Lopetegui was appointed Real Madrid coach to replace French manager Zinedine Zidane who quit his role after boss after he won the Champions League for the third consecutive time.
Twitter react as Spain sack coach on the eve of World Cup
Here are the reactions as Julen Lopetegui is sacked by Spain just before the start of their World Cup campaign.
The Royal Spanish Football Federation (RFEF) dismissed Lopetegui for not properly informing them upon developments of negotiations of the Real Madrid job.
Twitter users were divided upon the announcement of his sack, as some were of the opinion that he should have been allowed to take charge of the World Cup while others blamed him for not being transparent to his employers.
Here are reactions on Julen Lopetegui sack
A particular supporters was in favour of the decision and defended the decision of the RFEF to act.
He said, "This has got to be one of the weirdest decisions timing wise I’ve ever witnessed. The decision is justified but the timing is too sketchy."
Another supporter was of the opinion that the decision could cost Spain at the World Cup.
He said, "A day before the WC, #Spain can't afford to change the system, let alone the team. Hierro would have the idea of how #Lopetegui was going about his job and would only look to take it forward instead of doing something new."
Here are reactions on Fernando Hierro appointment
Fernando Hierro was appointed as Lopetegui's replacement which brought about several reactions on social media as well.
Fans on Twitter were also of divided opinion about the choice of Hierro as he only served as an assistant coach at Real Madrid.
A fan who was against the decision said, "Fernando Hierro's last job as coach saw him take Real Oviedo to an 8th placed finish in the Segunda. Now he'll lead Spain at the World Cup!"
Hierro will now have just one day to get his message across to his players as they take on Cristiano Ronaldo's Portugal in their opening group B game scheduled for Friday, June 15.