Suspended pending the outcome of an investigation into his failed drugs test, Toure turned up to support his teammates.
And he watched on as Ali al Habsi, Wigan's Omani international goalkeeper, gifted City all three points by letting David Silva's shot slip straight through his hands and between his legs.
Silva, the Spain midfielder, collected the ball just outside the Wigan box in the 38th minutes. He took advantage of Adrian Lopez's slip to create space for himself but it took an even bigger slice of luck to get the ball into the net as al Habsi inexplicably let it.
Al Habsi, the only Premier League player from the Gulf, then saw his teammates put in a spirited display, which could have earned them a draw.
Carlos Tevez almost scored for City in the first half as he collected Vincent Kompany's short pass and burst past Antolin Alcaraz. His finish for the far corner was just off target.
Wigan then wasted a glorious chance just before the half-hour when Victor Moses pulled a cross back from the byline and Kompany's weak clearance fell straight to James McCarthy 10 yards out.
With the goal at his mercy, McCarthy screwed it harmlessly wide, just before Silva struck.
Wigan came agonisingly close to levelling just after the break as Alcaraz crept to the near post to meet Ben Watson's cross, but the ball crashed against the bar and was cleared.
And in stoppage time, the substitute Conor Sammon missed a chance for Wigan to grab a deserved point, only for his shot to roll agonisingly wide of the par post.
* Press Association