Former Sunderland manager Martin O'Neill has warned the Premier League strugglers they might regret the decision to sack him.
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O'Neill was dismissed by the club's American owner Ellis Short just hours after last Saturday's 1-0 home defeat against Manchester United.
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Sunderland have gone eight games without a win in the Premier League and are dangerously close to the relegation zone.
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But O'Neill, who has since been replaced by former Swindon boss Paolo Di Canio, is convinced he would have kept the Black Cats in the top-flight if he had been allowed to remain in charge.
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The former Aston Villa and Celtic boss had already inspired a Sunderland team bereft of confidence and languishing in 16th place when he took over in December 2011, guiding them to a 13th-placed finish.
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"I am still pretty disappointed, frustrated as much as anything else but life goes on," O'Neill told BBC Radio Five Live on Friday.
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"I'm in the business now where I think very little shocks you about professional football especially in the last 10 years. You can lose a job in management if your tie doesn't fit your suit.
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"With the experience I have had over the years, also coming into the football club at a time when the club was pretty well on its knees, I believed I saved it from relegation last year and I thought that opportunity should still have been afforded to me."