In March, Martin O'Neill watched his players produce arguably their best display of last season as they became the only visiting side to take a point from the Etihad Stadium. Six months on, and rather than experiencing pride and satisfaction, the Sunderland manager was thoroughly fed up.
There is no disgrace in losing to a Manchester City side who are slowly rediscovering the form that propelled them to the title last season, indeed there is not even any embarrassment in suffering a three-goal reverse that was every bit as comprehensive as the scoreline suggests.
But there is always disappointment at a failure to meet the basic standards of competitiveness and performance, and for the first time this season, Sunderland fell way short of their standards as they ceded their unbeaten record.
“We were well beaten by a superior team,” acknowledged an honest O'Neill. “I would have very little complaint – indeed my only complaint is with us. It's just my thought, but I'm wondering if that total self-belief you need to come to a place like this was there.
“You can have all the self-belief in the world and you can still get beaten. Manchester City can turn over better teams than us. But it was the fact that we were second best all afternoon that was the most disappointing thing.”
Given the quality of Manchester City's attacking, especially in the second half when Sergio Aguero, David Silva and Carlos Tevez combined to produce a string of mesmeric passing moves, it would be wrong to read too much into Sunderland's failure to compete with their opponents.
The Wearsiders might have started the season with a five-game unbeaten run, but the fact that four of those matches were draws always suggested they were far from the finished article following a summer rebuild. Even the only win in the sequence – a 1-0 home success over Wigan – was a laboured affair.
Yet if the cup was never really more than half full, it would be wrong to suddenly suggest it is now less than half empty despite an unexpectedly parlous display.
Sunderland were defensively insecure from the moment Carlos Cuellar clattered into Tevez to concede the fifth-minute free-kick which Aleksandar Kolarov dispatched over the wall and beyond Simon Mignolet.
The wisdom of Cuellar's recall in place of Titus Bramble, who had performed admirably against Wigan, could perhaps be questioned, but Manchester City's creativity would have caused problems for any side in the league and Sunderland's back four remains generally reliable.
Mignolet, perhaps marginally at fault for the opener, redeemed himself with a string of excellent second-half saves, and is fast developing into one of the most effective goalkeepers in the country.
It is further forward where more genuine concerns remain, and Sunderland's only chances were a weak shot from Steven Fletcher that was easily claimed by Joe Hart and a looping header from James McClean that the City goalkeeper comfortably clawed away.
Fletcher remains the only Sunderland player to have scored a Premier League goal this season, and while Johnson's return should increase the club's attacking threat, it remains difficult to see where goals are going to come from if Fletcher is not firing. And goodness only knows what will happen if the newly-recalled Scotland international gets injured.
Sunderland's midfield is a riddle that has still not been satisfactorily solved, and for all his disciplinary issues, it is hard not to imagine that Lee Cattermole would have stiffened his side's resolve against City.
Was the skipper missed? “Lee was missing through his own fault, simple as that,” said O'Neill. “It's a difficult one for me to answer, but the better the players I have on the field, the better the chance we'll have.” So that's a yes then.
With Cattermole serving the second game of a three-match ban, Seb Larsson gave his all in an unfamiliar position. But neither the Swede nor Jack Colback was able to stem the flow of City attacking that became a torrent in the second half.
Aguero doubled the hosts' lead on the hour mark, stealing ahead of John O'Shea to convert the impressive Kolarov's left-wing cross, and after Silva floated a chip against the crossbar, James Milner sealed City's win with an 89th-minute free-kick that evaded Mignolet with the help of a deflection off Craig Gardner's head.
“It's disappointing, but we'll have to try to come again,” said O'Neill. They certainly will, as it is a certain club called Newcastle United that lie in wait next.