Middlesbrough 8 Manchester City 1
City suffered a cruel blow when skipper Richard Dunne was sent off after just 15 minutes.
The club's inspirational defender was shown a red card after a challenge on Tuncay in the penalty area. A penalty seemed a harsh decision, but as the last man Dunne had to go.
England international Stewart Downing made no mistake from the penalty spot for his ninth goal of the season.
Without the commanding influence of the club's player of the year, City were ripped apart by a side that delighted the home crowd with a brand of fast, attacking football.
For the visitors Martin Petrov blasted a free-kick over the bar and Stephen Ireland missed his kick on the edge of the penalty area.
Boro, however, were the more dangerous and it was no surprise when record buy Afonso Alves put them further ahead after 37 minutes.
From a Fabio Rochemback pass Alves gave Andreas Isaksson no chance with a shot into a corner of the net.
Isaksson was in action again shortly before the break, going down well to save from Alves and then George Boateng, when a goal seemed certain.
Downing piled on the agony for City with a magnificent left-foot shot that left the goalkeeper helpless just before the hour mark.
Ironically, manager Gareth Southgate wrote in his programme notes "I have set Downing a target of a brace so that he can finish in double figures".
Alves, who joined Middlesbrough mid-season for a club record of £12million claimed his second goal shortly afterwards, with a powerful shot that was parried by the goalkeeper but carried on over the goal-line.
Despite the scoreline the City fans were giving their team tremendous vocal support.
Both teams introduced substitutes with Adam Johnson making a quick impact for Boro with a deflected shot that beat Isaksson.
Rochemback followed up with a terrific strike in what could be his farewell appearance for Middlesbrough. City were in complete disarray by now and went further behind at 7-0 through substitute Jeremie Aliadiere.
The visitors claimed a consolation goal through substitute Elano, but Alves hit back to complete a hat-trick and give Boro an amazing eight goals for the afternoon.
City were completely outclassed as Eriksson possibly said goodbye to the Premier League in sorry style, despite the vocal backing of the City fans and banners of support among the away followers.