Trailing 2-1 to ten-man Bayern Munich, Aguero scored twice in the last five minutes to give the Blues a dramatic 3-2 victory that has turned Group E on its head.
In a game that ebbed, flowed and seemed to have died a death, City initially led, fell behind and then saved the best to last in the most memorable European evening for many years.
Has the the script for the Blues already been written? Time will tell
...City 3 Bayern 2...
The buzz before kick-off was mostly concerning the seeming reluctance of any of the three teams other than Bayern Munich to progress from this group!
CSKA’s last-gasp draw against AS Roma in Moscow meant the Blues’ hopes of finishing runners-up were still alive and kicking going into this match with numerous possible permutations meaning even a defeat against Bayern might not necessarily eliminate the Premier League champions.
The actual facts of the matter would become clearer when this game ended, but it did make people wonder if the stars were somehow aligning in City’s favour, despite a relatively poor Champions League campaign thus far.
Without Yaya Toure and Fernandinho through suspension and Edin Dzeko, David Silva and Aleks Kolarov through injury, you could argue Manuel Pellegrini had half his team missing for the toughest home fixture Group E has to offer
...City 3 Bayern 2...
But Bayern had the stellar talents of Messrs Muller, Schweinsteiger, Gotze, Dante and Shaqiri starting on the bench, so the Bundesliga champions were hardly at full strength, either.
The early exchanges were fairly even with both teams probing without much success, though City’s high press tactics certainly ruffled Bayern’s feathers early doors.
Then, midway through the half, the game exploded into life as City almost fell behind – then broke forward and won a penalty that resulted in the visitors being reduced to ten men.
It began when Eliaquim Mangala threw himself in the way of a shot from Rafinha who seemed certain to score, then Frank Lampard played a peach of a ball over the Bayern defence and Aguero was suddenly through on goal, only to be scythed down by Medhi Benatia in the box.
The referee had no other choice but to dismiss Benatia and award a penalty that Aguero duly planted home to give the Blues the lead their energy and industry just about merited.
With a man advantage and a goal to the good, City would surely never have a better chance of salvaging a Champions League campaign that had only brought frustration up to now?
The performance up to that point suggested this was to be the turning point, but all the hard work threatened to be undone in a crazy five-minute spell just before the break that sadly had become the trademark of this campaign
...City 3 Bayern 2...
First Xabi Alonso levelled with a free-kick that he almost passed into the net from the edge of the box as Bayern were allowed to post two players on the right of City’s defensive wall and a gap as big as the Mersey tunnel duly appeared as the Spaniard struck the ball.
Then, on 45 minutes, a deep cross into City’s box saw Robert Lewandowski force his way between Vincent Kompany and Bacary Sagna to shoulder the ball past Hart and give Guardiola’s men a 2-1 lead.
With the knowledge a draw might actually be a decent result, there was plenty of incentive for the Blues to go for broke after the break.
The Germans played with a freedom that only a team who have already qualified can and while that meant they would still attack in numbers, gaps seemed bound to appear in their defence as the game wore on – the key was staying in the game and not conceding again.
Lampard sent in a 25-yard drive that Neuer pushed over the bar, but the general play was scrappy and disjointed as City’s approach play became more desperate at the minutes ticked by and Bayern seemed to be in total control.
There seemed to be no way back as Bayern comfortably sat on their lead, then, a careless pass from Alonso was cut out by Stevan Jovetic and Aguero's electric pace took him clear and his low shot just evaded Neuer's fingertips to bring the Blues level.
But there was even more drama to come five minutes later as more sloppy defending - this time by Jerome Boateng - gave the ball Aguero on the edge of the box and the brilliant Argentine made no mistake as he calmly slotted home his third - and the winner - to send the home fans wild.
Incredible. Now to conquer Rome where a draw, depending on the Bayern v CSKA result, could be enough to send City through - though there are a number of scenarios it has to be said.
And remember, never write off the Mancunians...