It always seems obvious, after the event.
David Moyes had gone to shake Antonio Conte's hand on the touchline even before the final whistle. Chelsea would, in a scene typical of the embarrassment this season, go on to score another goal before it was all over.
At the final whistle, as had become his way, he scuttled down the tunnel without so much as a cursory glance at the travelling support.
It seems clear now that his mind was made up.
It was the right decision, of that there can be no doubt. This has been one of the worst campaigns in recent memory, Sunderland's pride battered and bruised after a sequence of tame implosions.
Moyes had tried almost every trick in the book with his squad this season. Tactically he had tried three man defences, four man defences. Two up top, one up top. Off the field he had criticised their quality, before starting to take a more sympathetic tone as the season developed.
The fundamental fact never changed, that he was utterly unable to get this squad to perform not just above their level, but even at it. There are many players who ought to feel a sense of guilt at their performances this season, seemingly caught in a hangover from Big Sam's departure, but the new man did nothing to lift their spirits or performances.
The key to this season's failure was that Moyes' signings, 13 of them, did not only fail to address to the squad's long-term deficiencies in pace and creativity but deepened them. Of all the 13, only Didier Ndong, and perhaps Bryan Oviedo at a push, is likely to be a regular next season. That was an appalling record as bad as Roberto de Fanti and Paolo Di Canio's.
Off the field, too, morale among the fanbase was as low as it has been for years, not helped by the manager's perceived negativity.
Moyes was supposed to be the man for Ellis Short all along, who would do what others had failed to and finally get a grasp of Sunderland's long-term problems. In the end, he only served to reinforce the idea that this has become a club without imagination, all too often appointing managers and signing players on a downward curve and coming to Sunderland sensing not a major opportunity but indeed a step down.
That must stop now. The next appointment must inspire and unite. David Moyes has done the right thing in leaving, giving the fanbase a chance to lick its wounds over the summer and attack next season with a renewed optimism.
The new manager must be hungry, forward thinking and be able to tap into a network of contacts to sign quickly and effectively.
It is a major, major task, but a relieved fanbase will be ready to throw their weight behind any manager who can inspire them.
Thoughts will turn to the future now, but when the dust settles on this season it will be remembered as a spectacular missed opportunity. Moyes inherited a side short on numbers but high on morale, and turned it into one of the worst in recent memory. He was not solely to blame for that, and many of this squad of players will depart to equal relief to those who have watched them, but his tenure will set alongside the likes of Howard Wilkinson and Lawrie McMenemy. Remembered not just for its failure but its inglorious nature, the morale sapping, soul destroying march to the drop.
Sunderland fans were told that this particular pain was all in the name of stability.
Now they are back in the corridor of uncertainty, a sense of a spectacular opportunity wasted.
It falls to Ellis Short to invest, to find the right manager and to put it right.