The Argentine striker proved to be the difference in an action-packed encounter at the Etihad Stadium, despite failing with one of his three attempts from 12 yards, with Christian Eriksen offering a solitary reply for a Spurs side that saw Premier League debutant Federico Fazio dismissed.
A game dominated by forward-thinking talent, with defences struggling at both ends of the field, was brought to life on 13 minutes when Erik Lamela was robbed of possession on the edge of his own box and Aguero was teed up to rocket a low drive beyond Hugo Lloris.
Tottenham’s response to falling behind was impressive, with Eriksen drawing them level inside two minutes as Fernando was caught on the ball and the Dane drilled home via the leg of Joe Hart and the underside of the crossbar.
There was to be no letting up, with Aguero restoring City’s lead from the spot 20 minutes in after Lamela was adjudged to have sent Frank Lampard tumbling inside the box.
The former England midfielder was then stretchered from the field before a clumsy lunge from Younes Kaboul on David Silva presented Aguero with another opportunity from 12 yards out – one he spurned as he fired down the middle and Lloris saved with his legs.
The breathless pace of the game continued after the interval, with both sides going close before another contentious penalty call offered Spurs hope just past the hour mark.
Martin Demichelis clipped Soldado’s ankles as the Spanish striker wriggled away from him, but a debate as to whether contact was made inside or outside the area was ended by Hart as he sprung to his right to beat the ball to safety.
Remarkably, referee Jon Moss then pointed to the spot for a fourth time on 68 minutes, with Fazio shown a straight red card for a tug on Aguero, freeing the South American to complete his hat-trick.
Spurs – who conceded 11 times in two meetings with City last season – were left with a containing job on their hands, but were breached again with 15 minutes remaining as Aguero beat the offside trap to cut inside onto his left foot and curl low into the bottom corner.
Spurs were thrashed 6-0 and were a goal down within a minute on the same ground 11 months ago. They performed much better this time but the end result was that the champions still had too much for them.
They started well with Ryan Mason dragging a shot wide and then being denied when clean through by Hart. The England goalkeeper was in action again moments later as he tipped over an Eriksen drive.
City looked much better in attack than defence and Silva almost put Aguero through before Jesus Navas tested Lloris.
Lampard, starting ahead of the presumably rested Yaya Toure, then robbed Lamela to set up the first goal, although Aguero still had plenty to do.
The Argentinian actually seemed to have few options on the left of the area but he opened his body and clipped a superb shot inside the far post.
Spurs produced an immediate response as Mason robbed Fernando and Soldado released Eriksen to smash a powerful shot in, off Hart and then off the underside of the crossbar.
But the visitors could not retain parity for long as Lampard exchanged passes with Milner and then went down under a challenge from Lamela in the area.
Moss had little hesitation in awarding the penalty and Aguero stepped up to fire home his second.
City looked impressive in possession but their rhythm might have been disrupted when the influential Lampard appeared to suffer a thigh injury and had to be carried off just before the half-hour.
Yet the hosts pressed on and Aguero might have had his hat-trick – when he shot straight at Lloris – even before being presented with a second spot-kick as Kaboul felled Silva.
Lloris saved well from Aguero and the striker put the rebound over with a scissors kick.
Spurs looked to make the most of the reprieve but Hart produced another fine save to keep out a Mason drive and also palmed away a long-range Eriksen effort.
A frantic first half ended with Lloris saving from Navas and the second began with the same man stopping an Aguero shot. Navas was also frustrated in front of goal before Aguero failed to connect with a Silva cross by inches.
There was another dramatic twist just after the hour as Demichelis was adjudged to have brought down Soldado.
But the third penalty awarded became the second one saved as Hart plucked Soldado’s shot out of the bottom corner with a full-stretch dive.
The England keeper had to be alert again moments later as Soldado connected firmly with a cross and he saved with his feet.
City weathered that storm but it took another moment of controversy for them to gain firm control.
This time Spurs league debutant Fazio was deemed to be in the wrong, pulling back his countryman Aguero off the ball and in front of goal to earn a red card.
This time Aguero made no mistake from the spot and he was still far from done, scoring a fourth as he chased down a long ball from Fernandinho and curled in another fine shot.
Spurs were already beaten as Toure came on for the final 14 minutes as Milner almost added to their woes with a curling shot that struck the post.