Martin O'Neill has parted company with Sunderland after the Black Cats slipped deeper into relegation trouble.
The 61-year-old's departure was confirmed hours after this afternoon's 1-0 home defeat by Manchester United, which left the club sitting just a point clear of the Barclays Premier League relegation zone with seven games left to play.
A club statement said: "Sunderland AFC has announced that it has parted company with manager Martin O'Neill this evening.
"The club would like to place on record its thanks to Martin and wishes him well for the future.
"An announcement will be made in the coming days regarding a successor."
Short has been unhappy with results for several weeks, but writing in his programme notes today, he called for a united front.
He said: "Of course, there is nobody that is happy with our current position and the way our season is going. The reality is that we have a fight on our hands with eight games remaining.
"We know that we are capable of playing better than we have been doing and we know that we need to begin doing so now.
"I can assure you that every person at the club is doing everything they can to ensure that the season ends on a positive note and when the season is over, we can take stock of what happened.
"Right now, however, there is only one thing that every one of us should be focused on, and that is doing our part whatever that is in helping this team to get the points we need.
"I'm very aware that our supporters, who have backed us week in, week out in such huge numbers, aren't happy and fully understand why.
"But right now, it is important for us all to be on the same side and get behind the team. Not being together will not help us to get results, so let's stand shoulder to shoulder and give the team our full support."
That stock-taking exercise was dramatically brought forward this evening.
O'Neill was seemingly not expecting the development as he conducted his post-match press conference.
He said: "I am as buoyant now as - I was nearly going to say as I have always been.
"What is it - the half-full or the half-empty glass? I'm even going to the three-quarters full.
There's a real determination in the dressing room. The players are obviously disappointed, but they can take a lot from the second half.
"Yes, there is a determination about the players in there that we can do it."
It is understood the search for a successor is already under way and that the club hope to make a swift appointment.
However, whoever gets the job faces the task of galvanising a squad for an intensely uncomfortable run-in with the stakes higher than ever as a result of the cash implications of the new broadcasting deal.