Sevilla made official the departure of coach Julen Lopetegui after the team's 4-1 home loss to Borussia Dortmund in the Champions League on Wednesday.
The Spanish club is expected to announce the return of Jorge Sampaoli in the coming days.
An emotional Lopetegui bid farewell to fans who chanted his name after the match.
"I'm very thankful for everyone and very sad to leave a club that I love very much," Lopetegui said. "Sevilla will forever be in my heart."
The loss to Dortmund virtually ended Sevilla's chances of advancing to the last 16 of the Champions League. It had already lost 4-0 at home to Manchester United and drawn 0-0 at Copenhagen. Sevilla trails Borussia Dortmund by five points and Man City by eight points after three group-stage matches.
Lopetegui was with Sevilla for three years, leading it to a Europa League title in 2020 and consecutive fourth-place finishes in the Spanish league. The team is currently 17th after one win, two draws and four losses to start the season.
There had been high expectations entering this season but Lopetegui leaves with the club having won only once in 10 matches in all competitions - at Espanyol in the fifth round of the Spanish league.
His firing was considered only a matter of time as the negotiations with Sampaoli had been widely reported by Spanish media.
"I don't want to talk about whether there was lack of respect toward me or not," Lopetegui said. "This is not the time to talk about that."
Lopetegui was scheduled to take part in a farewell event with the club on Thursday. Sevilla made the announcement of his firing with a social media post and video thanking him for his time as the team's coach.
In 170 matches with Sevilla in all competitions, Lopetegui led the team in 89 wins, 45 draws and 36 losses.
The 56-year-old coach has been linked with the vacant manager's job at English team Wolverhampton.
Lopetegui attracted worldwide headlines after being fired as Spain's national team coach just days before the start of the 2018 World Cup in Russia for taking a job with Real Madrid without telling Spanish soccer federation officials in advance.
Sampaoli managed Sevilla in 2016-17 before leaving to take over the Argentine national team.