Sunderland have sacked head coach Paolo Di Canio with the Black Cats bottom of the Premier League table.
The 45-year-old Italian has won three of his 13 matches since in March and taken only one point from five league games this campaign.
Sunderland said they will decide on Di Canio's successor in "due course".
Coach Kevin Ball will take temporary charge of the team, with ex-Chelsea boss Roberto Di Matteo an early favourite for the job.
Former Brighton manager Gus Poyet is also believed to be a contender but he has refused to comment on reports linking him to the post.
Di Canio's dismissal leaves Sunderland looking for their sixth permanent manager in less than five years.
The Italian's backroom team of first-team coach Fabrizio Piccareta, goalkeeping coach Domenico Doardo, fitness coach Claudio Donatelli and physio Giulio Viscardi will also leave the Stadium of Light outfit.
Sunderland's statement added: "The club would like to place on record its thanks to Paolo and his staff and wishes them well for the future."
Senior professional development coach Ball's opening duty as caretaker boss is to prepare the side for Tuesday's home Capital One Cup third-round match against Peterborough United at the Stadium of Light.
Sunderland then host Liverpool on Sunday and Manchester United on 5 October, with the Wear-Tyne derby against Newcastle on 27 October.
Di Canio started out as a player in Italy and was a forward for Lazio, Juventus, Napoli and AC Milan before a move to Scottish giants Celtic.
He had spells in the Premier League with Sheffield Wednesday, West Ham United and Charlton Athletic before returning to Lazio and finishing his playing career at Cisco Roma.
The Italian began his managerial career when he took over as Swindon boss in May 2011 and guided the club to promotion from League Two in 2012 before resigning in February 2013.
Di Canio then succeeded Martin O'Neill at the Stadium of Light on 31 March and signed a two-and-half-year deal, although he later admitted he in the immediate controversy over his arrival.
Embarking upon his first Premier League job, Di Canio had to fend off questions about whether he held fascist beliefs.
He was backed by Sunderland chairman Ellis Short and endeared himself to the fans with a in his second game as boss.
But Di Canio's men were and failed to win their final three fixtures, finishing only one place above the relegation zone.
This season started with a home loss to Fulham before the Black Cats drew at Southampton and conceded nine goals in defeats against Crystal Palace, Arsenal and, most recently,
After the 3-0 loss at The Hawthorns on Saturday, Di Canio walked over to face the travelling supporters, who made their feelings clear.
"I absorb the insults as it's part of the game - if I was in their position I'd be furious," he said. "But I'm professional: 24 hours a day I work for this cause. One day their reaction will be a different reaction.
"I knew that they were furious. I went to them because I wanted to see their faces. It's easy to go over when they're clapping or singing your name. I'm responsible but my head is up. I won't give up.
"It's obvious we're still not together. We don't have many leaders in terms of desire to play with a premier style.
"I'm never going to change my regime. I am what I am. My way to manage the team is for the top, top level. I have to be clear to everyone - the board, the chairman, the fans - I'm never going to change.
"One day, if I receive the full support from the players, we will turn the corner."
Di Canio some of his squad at the end of last season and worked with director of football Roberto De Fanti and chief scout Valentino Angeloni to sign 14 new players in the summer.
His buys cost £19m in total and included AZ Alkmaar striker Jozy Altidore, Italy international Emanuele Giaccherini and Arsenal goalkeeper Vito Mannone.
But left-back Danny Rose returned to Tottenham following a loan spell, while Sunderland sold goalkeeper Simon Mignolet to Liverpool and, on transfer deadline day, attacking midfielder Stephane Sessegnon to West Brom.