Although there is still one game remaining this weekend, Wednesday night's encounter between City and Tottenham at Eastlands has been billed as a Champions League decider.
If Tottenham win, they cannot be caught in fourth. For City it would open up a whole new world, which the huge amount of cash at their disposal makes them ideally placed for.
The enormity of City's potential seems to have inhibited them in recent weeks.
But, after rallying to beat Aston Villa at the weekend, now Mancini knows the Blues are approaching their date with destiny.
"I know this is an important moment for the club," said the Italian.
"We have worked for this. All the players have worked for this target.
"I have worked here for five months. I can build a good future here. We are trying to change the history of the club."
As Mancini's arrival came as a direct result of fears amongst the ownership that City would fail in their top-four quest if Mark Hughes remained as manager, he can hardly avoid the inevitable question marks about his own future at Eastlands.
Yet the former Inter Milan coach insists he will remain next season, no matter how this one ends.
"My future does not come down to this game," he said.
"We have qualified for the Europa League next year, that is important.
"Now we have a chance to do more."
Mancini certainly appears happy enough.
Although it is hardly a surprise for him to state progress has been made since he arrived at the club in December, there is a sense of City becoming a more formidable, if less exciting outfit.
Certainly no-one will be interested in the entertainment value tomorrow, when the result tramples over any other consideration.
Mancini is determined his players should not be affected by the situation, although, on the training ground at least, he sees no sign.
"There is no pressure. It is a football match not a war," he said.
"If you are not happy where you work I don't think you stay. I am happy because I want to build a good team here
"Being in the Champions League would allow us to progress. It is important for the club and everyone here.
"But we must not be nervous and I don't think the players are. They are all concentrated."
Although Joleon Lescott has been ruled out of the run-in with a hamstring injury, City could have Gareth Barry available after the midfielder missed Saturday's victory over his former club with a similar problem.
Victory will leave City needing to win at West Ham on Sunday to confirm their position among Europe's elite, which does not create much room for any other topic in Mancini's mind.
There is no discussion of potential summer targets - the latest links are for Benfica duo Angel Di Maria and David Luiz - just a total focus on the task ahead, knowing Tottenham will be going through exactly the same process.
"Tottenham are a good team," said Mancini.
"They have very good players and a good manager, who is very experienced.
"They have been fantastic in the Premier League this year. Now Tottenham and ourselves must play for fourth position. It is fantastic for us and them.
"I can see how much people here want this. I would like all the people who work here and come tomorrow to leave with a good feeling.
"I like this situation."