Royal Spanish Football Federation (RFEF) president Luis Rubiales insisted there was "no mutiny" from the players after the sacking of Julen Lopetegui .
Lopetegui was stunningly sacked as Spain coach on Wednesday, just a day before the beginning of the World Cup.
It came just a day after it was revealed Lopetegui was taking over as Real Madrid boss , news Rubiales says he only found out minutes before the announcement.
Amid reports the players had pleaded for Lopetegui to remain in charge , Rubiales insisted the squad were happy ahead of the showpiece tournament.
"I have listened to everyone, but the decision is mine," he told El Partidazo de COPE .
"The players are completely determined to make a great World Cup. There is no mutiny, the players are doing very well."
Real Madrid great Fernando Hierro will lead Spain – who face Portugal, Iran and Morocco in Group B – at the World Cup.
Rubiales said the appointment of the 50-year-old had been well received by the players.
Más unidos que nunca. Tan fuertes como siempre #HagamosQueOcurra #Rusia2018 https://t.co/9DuBvHp4XW
— Selección Española de Fútbol (@SeFutbol) June 13, 2018
"The players have welcomed Hierro and have told me they will be with him to the death, with [Sergio] Ramos very well, acting as captain," he said.
Spain begin their campaign with a clash against Portugal in Sochi on Friday.