Ji Dong-won blew the race for the Barclays Premier League title wide open once again yesterday as Manchester City wasted a chance to establish a three-point lead.

The South Korea came off the bench to launch 2012 in style on Wearside with an unlikely winner in the fourth minute of injury time, when he looked to be fractionally offside before slotting in.

Fellow substitute Micah Richards had hit the woodwork at the other end with just a minute of the 90 remaining, and with Sunderland staging a valiant rearguard action.

Yet, a day after Manchester United and Chelsea both slipped up, City were unable to take advantage despite creating a host of chances as they were shut out for the second successive game.

Sunderland's new manager, Martin O'Neill, said: "They tell me [the goal] was marginally offside – marginally, marginally – and we ended up winning the game.

"It's been an incredible weekend for teams and we are delighted with three points."

Roberto Mancini, who headed down the tunnel before the final whistle, admitted his side had been made to pay for missed chances.

He said: "It's frustrating. In the second half, we had I don't know how many chances to score. But football is this. Sometimes you can't win. Sometimes you score three or four goals in a game, sometimes you can't score even if you have 10 chances to score."

O'Neill, who insisted he had no problem with Mancini's early departure at the end of the match, was thrilled to have secured the points. "It was a fantastic effort, really, really fantastic," he said

Mancini, perhaps with one eye on tomorrow's home game with Liverpool, had started with Sergio Aguero and David Silva on the bench and left Mario Balotelli out of the 18, but he was forced to bring on the star pair in a desperate search for a winner.

Yet, had either Nicklas Bendtner or Stephane Sessegnon taken the chances which fell their way either side of the break, Sunderland might have been in front long before they did actually take the lead.

O'Neill had gone into the game without a specialist full-back as injuries tore his defensive resources apart, and the situation was to get worse long before the half-time whistle sounded.

Having already had to press midfielders Craig Gardner and Jack Colback into service at right-back and left-back respectively, he also had to draft in goalkeeper Simon Mignolet for the first time since he fractured his nose and a eye-socket on October 29 as Keiren Westwood pulled out.

O'Neill was forced into a further change with just 26 minutes gone when centre-back Wes Brown pulled up and was replaced by Matt Kilgallon, making his first senior appearance for the club since May 2010.

In the circumstances, O'Neill could hardly have been more pleased with the way his distinctly makeshift defence battled its way to the break without conceding.

Mancini had seen enough and replaced defensive midfielder Nigel de Jong with Aguero at the break. But it was Sunderland who should have gone in front with 64 minutes gone when Sessegnon cut inside from the right and found himself with just Hart to beat. However, he pushed his shot agonisingly wide of the far post.

Richards went desperately close to a winner with a minute of normal time remaining when he headed the ball into the ground and saw it come back off the crossbar after Mignolet had parried Silva's shot.

However, the drama was not over and when Sessegnon stabbed the ball into Ji's path, he calmly rounded Hart to snatch three precious points.