South Korea's Ji Dong-Won struck in injury time as Sunderland inflicted a shock 1-0 defeat upon Premier League leaders Manchester City.
Sunderland bring Manchester City back to earth
At the end of last week, displaying the sense of humour that has become more apparent as his English has improved, Roberto Mancini joked that it had long been his ambition to spend New Year in Sunderland.
It was said with a smile, but the frowns of frustration were on the Manchester City manager's face long before they were replaced with a look of astonishment when he heard about Ji Dong-Won's late winner.
As City were condemned to a second defeat of the league season, Sunderland, it transpired, was far from the ideal place to begin 2012, one where it became harder for Mancini to realise his ambition of winning the title.
Even a draw would have been an inadequate reflection of the pressure his side exerted and the chances they spurned.
Instead, with four seconds of added time remaining, their point disappeared as Ji collected Stephane Sessegnon's pass, slalomed past Joe Hart and tucked the ball into the unguarded net.
It was so late that Mancini himself had not seen it, having headed for the dressing room.
"Because the game was over," he said. "I can't believe it. I am really disappointed."
The goal was, as he noted, marginally offside, but it prompted an almighty roar at the Stadium of Light.
"Just fantastic," said Martin O'Neill.
His is a rejuvenated club, one that can testify to potency of the O'Neill factor.
The Northern Irishman's five games in charge have brought three wins, all sealed by late goals. This is a side that retains its belief to the final whistle.
Even when they are facing the league leaders and are so depleted by injuries and illness that midfielders occupy both full-back positions and a player who had seemed an outcast - Matt Kilgallon - played for an hour in the centre of defence.
Behind them was a goalkeeper, Simon Mignolet, who was making his comeback in a mask after fracturing an eye socket.
"He has done four or five days' training," said O'Neill.
"His performance was fantastic."
With the assistance of his woodwork, Mignolet kept a clean sheet, another of the ingredients of an improbable triumph.
"It was a remarkable performance by the team," the manager added after a virus hit his squad.
"We had a lot of problems beforehand, problems during the game and problems with Manchester City.
"They are a really top-class team."
It was a smash-and-grab raid - "Backs to the wall," O'Neill described it - with Sunderland being camped in their own half for the majority of the game.
And yet they carved out three wonderful opportunities, each involving the mercurial Sessegnon.
His contributions bookended the game.
In the third minute, Sunderland broke at pace, Sessegnon expertly steering a pass through to allow Nicklas Bendtner to gallop through on goal.
The striker opted to take the ball around Hart, an approach that backfired when the goalkeeper blocked his shot.
Later Sessegnon illustrated his ability with a wonderful turn to baffle Vincent Kompany only to mar his fine work by placing his shot past the post.
But much of the drama occurred at the other end.
City had 19 attempts on goal, with Edin Dzeko launching a one-man assault.
He is a striker who deals in boom and bust in front of goal.
Many do, but the Bosnian is an extreme case. His drought reached nine games, but he was desperately close to ending it when a ferocious half-volley grazed the bar.
That was unfortunate.
He was, too, when Mignolet made a close-range block after Dzeko spun to unleash a shot.
But when the target man twice shot over and twice headed wide, he was profligate.
Others could have brought the breakthrough, too.
The emergency right-back Craig Gardner cleared Samir Nasri's shot off the line.
After Mancini had sent on Sergio Aguero and David Silva, whom he had hoped to spare for Tuesday's game with Liverpool, the Argentine was denied by Mignolet.
It was an occasion when squad rotation backfired, with City subdued for the first half-hour and looking likelier with the introduction of three of their premier players.
Indeed, while a late winner ended up in the script, but it was almost scored by City.
Silva's drive was parried by Mignolet and Micah Richards, the third replacement, headed the rebound against the bar.
"In the second half we had a lot of chances to score," Mancini said.
"We deserved to win this game. We can't concede a counter attack like this."
But they did as New Year in Sunderland turned sour for him.