It was a lavish statement of intent, one that has barely relented since that memorable 2008 day.
The men from the Middle East have backed City to the hilt, willing to provide whatever is necessary for the club to win the Premier League, a dream that is on the verge of becoming a reality.
10 years ago in 2001-02, City were clinching promotion into the Premier League, after relegation the year before.
Critics will argue City's spree - a net spend of more than £350 million since Mansour's arrival - is vulgar, or even unfair, surely a different word is more apt; necessary.
To win the Premier League title is simply an impossibility for most teams. Barring the top five or six sides, such a quest is unimaginable.
Even for a side like Liverpool, to make such a leap from their current position, it just does not seem possible.
For Manchester City, a club who finished ninth before Mansour arrived and 14th the year before that, it would have been impossible to reach the top of the mountain without a billionaire investor.
Mansour shook things up, and his commitment should be welcomed not scorned.
Cast your minds back to 2007-08. The Premier League was a dull affair by comparison to now, 'The Big Four' dominated.
Manchester United, Chelsea, Arsenal, and Liverpool had locked down the top four spots in five out of the preceding six seasons including that one, with Everton's fourth in 04-05 providing the exception. The big teams were only looking like becoming more and more powerful.
With the top four a foregone conclusion, it offered little hope to the rest of the teams, who simply could not break into it. Only investment could surely change that?
Not only that, but since and including 2004-05, only Chelsea and Manchester United have won the Premier League. A duopoly to resemble Madrid and Barcelona, one which finally looks about to be broken.
The second that Mansour arrived, the top four were put on notice- a new team was coming for their spots.
City changed the landscape of English football, spending millions on players other teams likely would have snapped up, turning Arsenal into a feeder club and overtaking them in the process.
Liverpool buckled first, but it was Tottenham Hotspur who beat Mansour's men to it. City's resurgence had given other clubs the belief that reaching the top four was suddenly possible, themselves stumbling from Mark Hughes to Roberto Mancini, a decision which has served them well.
Say whatever you like about the spending spree, but without it Manchester City would never have been able to challenge for the league title.
Yes Newcastle and Tottenham have joined the party, but both are a long way off from taking the huge next step, and a big investment would be required to turn either into genuine challengers.
City have mixed things up, it was what was needed, and it was the only way to do it.
Now the club are at the top, they can scale back a degree, and by investing in a youth academy they are looking to a more sustainable future.
The money has brought terrific players to the Premier League for neutrals to enjoy. Sergio Aguero, Yaya Toure, David Silva, and the box office that is Mario Balotelli. Surely that is no bad thing?
In America the NFL uses what they call a draft- with underperforming teams getting picks of the best prospects, a salary cap, and strict financial structure, to ensure 'fairness'
This is to stop the best teams getting further and further ahead, as they had been, and to allow others to catch-up without plying in 'vulgar' sums.
Had any similar enforcement or structure existed in football, City could have caught up via different means. But the game as it is, with the rich getting richer, and the have-nots getting further left behind, spending such sums was quite simply the only way for the blue half of Manchester to put their red neighbours in the shade.
Such a mechanism is being drawn up by Michel Platini at UEFA with the much-talked about Financial Fair Play regulations, which ironically could see City suffer. Had they been in place all along, perhaps the Blues could have risen to the top without a need to over-exert the finances.
Mansour and City have changed the Premier League, and it is hard to argue it is not for the better, despite what their detractors may say.
image: © Gene Hunt