Robinho signed off with a flourish at Glanford Park with an 84th minute goal to seal victory for Manchester City in what will probably prove his last game for the club.
The £32million Brazilian started the day by telling a radio station in his home country he was leaving Eastlands and ended it with the goal to secure a place in the FA Cup fifth round.
Robinho had made little impact on a fiercely-fought cup tie in which Nigel Adkins' Coca-Cola Championship strugglers refused to give in to Roberto Mancini's millionaires.
Despite Martin Petrov's third minute opener the home side hit back to equalise through Paul Hayes - then Cliff Byrne created more anxious moments to reduce deficit after goals from Nedum Onuoha and Sylvinho.
Until his almost inevitable parting shot, Robinho's likely exit had been an inauspicious one under a barrage of pressure from the Championship side.
His only other mark on the game came in the third minute when he followed a flurry of step-overs by feeding Petrov on the left to crash the opener past Joe Murphy.
That apart Robinho was relegated to the role of a virtual passenger as his side struggled to shrug off their persistent opponents amid a white-hot atmosphere.
If City's megastars thought Petrov's goal would take the sting out of their opponents they were sadly mistaken as Scunthorpe pressed in search of an equaliser.
Martyn Woolford cut inside before firing a long-range effort across Stuart Taylor's goal in the 10th minute, and five minutes later the home side came even closer.
Paul Hayes played Marcus Williams into the left side of the box and only a saving challenge by Abdi Ibrahim helped City shepherd the ball out for a corner.
Cliff Byrne got his head to McCann's corner only to see it hammer the underside of the bar then bounce down for Vincent Kompany to boot clear. Hayes then screwed a shot on the rebound wide.
With chants of "what a waste of money" greeting Robinho on the rare occasion he touched the ball, the home fans were revelling in a hard-fought tie.
Petrov came close to a second in the 26th minute when he curled a shot from the opposite flank which was held well by the diving Murphy.
But he home side grabbed their richly deserved equaliser in the 29th minute when McCann's short corner led to confusion in the City box and Hayes found space to volley into the top corner.
As confidence continued to flood through the home side Gary Hooper blazed over the bar while Robinho's similar attempt at the other end almost cleared the stand and drew more jeers.
But City nudged back ahead in the final minute of a busy half when Stephen Ireland threaded a neat ball into the Scunthorpe box and Onuoha shot home from a tight angle.
Sam Togwell had the first chance of the second half in the 54th minute when he was cued up by Hooper to hit a long-range shot which Taylor did superbly to tip over the bar.
The ever-dangerous Petrov lashed another left-foot effort just wide after a neat lay-off from Robinho before Sylvinho effectively wrapped the tie up in the 57th minute.
The Brazilian was fed the ball 35 yards from goal and unleashed a stunning left-foot strike which beat the helpless Murphy and crashed into the top corner of the net.
City almost grabbed a fourth in the 64th minute when Petrov's fierce shot was deflected out for a corner, from which keeper Murphy twice blocked shots on the line.
But Scunthorpe found renewed hope in the 69th minute when McCann floated in a corner from the right which dropped for captain Byrne to stab home from close range.
The home side pushed for an equaliser but the final say just had to fall to Robinho, who was fed by Petrov before lifting the ball into the roof of the net.
The Brazilian was substituted almost immediately and made a point of shaking hands with each member of the City bench with his brief career at Eastlands seemingly over.Reuse content