The Blues scored three goals in each half to emphatically swipe aside the Terriers 6-1 at the Etihad - a statement of intent if ever there was and the perfect way to start the home campaign.
The visitors came to defend in numbers and frustrate.
David Silva was at the heart of most of City's creative probings and Gabriel Jesus twice had chances to open the scoring in the opening minutes only to be denied by keeper Ben Hamer.
It seems the best way to foil any seemingly solid defensive plan is to do something a little different, so when the visitors saw the ball at Ederson's feet, there seemed little to worry about - but one pinpoint 70-yard pass later and City were about to strike.
The pass found Aguero, who still had plenty to do as he controlled the ball from his goalkeeper, but crucially, he was in behind the Terriers' defence.
He had one man-marker to worry about and after he'd worked himself a yard of space. he deftly chipped the ball over Hamer and the back-tracking Terence Kongolo on the line to put the Blues 1-0 up on 25 minutes.
Six minutes later it was 2-0.
Benjamin Mendy burst forward and exchanged passes with Gabriel Jesus before the ball fell loose to the Brazilian on the edge of the box and he immediately fizzed a low shot into the bottom corner with Hamer unsighted.
The only blip on an otherwise peerless first half was moments before the break when Billing's throw was flicked on by Mounie and and Stankovic poked in from close range.
No matter - City restored a three-goal advantage just three minutes into the second half with a wonderful free-kick from 20 yards from David Silva that left Hamer flat-footed - the perfect way to mark his 250th Premier League appearance on his son Mateo's first Etihad visit.
Aguero then came close to another hat-trick on 57 as he skipped away from a couple of challenges before firing a low shot against the foot of the post from outside the box with the visitors reeling.
Of course, with so long left, it was almost inevitable that the Blues would inflict further damage and it came on 75 minutes as Mendy sent in a fine low cross and Aguero deftly volleyed past Hamer from close range for yet another hat-trick in sky blue - his 13th in fact - to make it 5-1.
Kun's reward was to be replaced by Leroy Sane seconds later and the German winger almost grabbed a sixth goal shortly after as he raced into the box only to see his shot saved - but Kongolo finished the job as the ball hit his knee to make it 6-1 five minutes from the end of a long afternoon for the West Yorkshire side.
There could have been more in the time that remained, but nobody was complaining as the champions left the pitch to a standing ovation.
Man of the Match: Sergio Aguero
Hat-trick No.13 for the Argentine who looks fit and razor-sharp. Could this be his best season yet ? He's already got five this season and is well on his way to 300(!)
City looking in fine fettle
Some of the approach play was delightful as the champions sent out a warning that it is business as usual despite the loss of Kevin De Bruyne.
Bernardo Silva was bright and inventive and playing two strikers proved too much for the Terriers to cope with.
The City defence will have many busier afternoons than this in the games to come, but it was important to post a warning to sides coming to defend that there is no hiding place against Pep Guardiola's relentless, well-oiled machine.
Silva: Rolls Royce performance
Simply superb and worthy of the man of the match award - had Sergio not bagged a treble - David Silva seems ageless.
At the heart of all City's best moves for an hour or more, he capped appearance No.250 with a delightful free-kick to get his campaign off an running with a display that suggests he is going to be pulling the strings for the Blues for many seasons to come.
Reaction: Pep Guardiola
"We suffered last season a lot against Huddersfield - we had problems to attack more fluidly. Teams defended with four or five at the back, or deep - even the strikers go deep to help the holding midfielders.
"Last season, we did it once or twice but not much more. We decided to play with two strikers to have more of a presence in the box, knowing we also have Mendy arriving. He is clever - he can see the pass in front of the ‘keeper, or the penalty spot, or the 18-yard box. He is a clever guy, arriving there.
"Today, it worked but that does not mean every time, we will play in that way. It depends on the players we have and the players that play.
"The way we attacked and our desire without the ball was perfect. We started with a lot of people coming back later. That showed in the Community Shield and against Arsenal and today, we were much better in terms of football and consistency. Against Chelsea and Arsenal, we survived rather than played well.Attacking with ten players in the box, we did quite well."
City travel to newly-promoted Wolves next Saturday, kick-off at 12.30pm.