Julen Lopetegui apologised to supporters after Sevilla suffered a shock elimination from the Copa del Rey at the hands of second-tier Mirandes on Thursday.
Sevilla succumbed to a 3-1 loss in the last-16 match at the Municipal de Anduva, with Matheus Aias sending Mirandes into half-time with a 2-0 lead.
Lopetegui made three substitutions at the break and his side was lucky the Segunda Division side did not extend its lead when Diego Carlos conceded a penalty by fouling Alvaro Pena, who saw his effort from 12 yards kept out by Tomas Vaclik.
Alvaro Rey put the result beyond doubt five minutes from time, with Nolito's 90th-minute goal providing scant consolation.
"We apologise. We are all tremendously sad, but we have to back up quickly," said Lopetegui.
"We were prisoners of our bad start and they took advantage to get ahead. In this format, one bad game means you are eliminated.
"The first goal was key. It gave them a lot of energy and generated doubts [for us].
"When three substitutions are made, it's because the first one to make a mistake was the coach.
"We tried to score early in the second half but everything was against us. The goal we expected did not come and we have been eliminated by a good team that was superior.
"It's a big blow, without a doubt. We were very excited, but we have to pick ourselves up."
Mirandes will be the only team from outside LaLiga in the quarterfinal draw on Friday.