Julen Lopetegui said Thursday that the day he was sacked as Spain coach was the "saddest" since the death of his mother as he was officially unveiled as Real Madrid's new manager.
"Yesterday was the saddest day of my life since the death of my mother. But today is the happiest day of my life," Lopetegui said as he fought back tears.
"We are convinced that we acted in an absolutely honest and clear way."
Spain's World Cup preparations were thrown into turmoil on Wednesday as the Spanish Football Federation (RFEF) sacked Lopetegui after Real Madrid confirmed he would take over at the Bernabeu for next three seasons.
Spain players reportedly resisted his sacking, which came as Spain are due to face European champions Portugal in Sochi on Friday before taking on Iran and Morocco in Group B of the tournament.
Lopetegui, 51, said he wished federation chief Luis Rubiales "had handled things in another way."
There were fears Lopetegui's appointment by the European champions could open up old divisions between the Real Madrid and Barcelona factions in the Spain squad.
Real Madrid president Florentino Perez called the Spanish football federation's reaction to the club's signing of Lopetegui "disproportionate, unfair and without precedent in the world of football in similar cases.
Perez also lashed out at what he called "an absurd reaction of misplaced pride" on the part of Rubiales.
The federation named Fernando Hierro, 50, as an emergency replacement at the World Cup despite having only one season's managerial experience in the Spanish second division with Real Oviedo.
He was popular among the players as the federation's sporting director between 2007 and 2011, and returned to that role in November of last year.
New man in charge: Julen Lopetegui gives a speech during his official presentation by Real Madrid on Thursday