And Aguero became the Premier League’s greatest overseas goal-scorer with his second goal of the night on 57 minutes as he wriggled past a couple of challenges before burying a low shot into the bottom corner from 15 yards.
Aguero completed his record haul of hat-tricks nine minutes from time to cap a memorable day for him and City.
Villa pulled a consolation back from the penalty spot in stoppage time.
City now move to within 14 points of leaders Liverpool, while Villa slipped deeper into relegation trouble.
Champions continue perfect start to New Year
There has been a school of thought that suggests City are back to their very best in recent weeks.
In the first half against Manchester United in midweek, City were at their irresistible best – and the same could be said of the opening period against Villa - and beyond.
That ability to blow teams away before the break that helped secure back-to-back titles has not been as evident this season – but it most certainly has in the past two games with both United and Villa taken apart on the opening 45.
And there was no let up after the break - something that will please the manager.
With AymericLaporte and Leroy Sane both nearing full fitness, we could be in for a very exciting second half of the campaign.
Mahrez oozes class – Aguero confirmed as greatest
Riyad Mahrez’s first goal was one of a player at the very peak of his powers.
Picking up a pass midway inside the Villa half, the Algerian winger raced into the box, jinked inside one challenge and with thee defenders ahead of him, tucked a low drive inside the post.
His second was thanks to the persistence of Aguero, keeping the ball in play when all seemed lost and when Danny Drinkwater , making his debut,then dithered in possession, David Silva poked the ball to Mahrez who thumped home from eight yards.
Aguero drew level with Arsenal legend Thierry Henry as the greatest overseas goal-scorer in Premier League history with a sublime strike from 20 yards.
And the irrepressible De Bruyne provided his second assist of the game with the sort of burst forward and low cross that only he can provide to give Gabriel Jesus the simplest of tasks.
Aguero, who had been writing history at Club and Premier League level for some time, moved on to 176 league goals just before the hour with the sort of goal that has been his trademark over the years, powering past a couple of challenges before placing a low shot just out of the keeper’s reach.
On 81, he fired home yet another City hat-trick with a low drive from close range - incredible.
Man of the Match: Sergio Aguero
What can you say about this man that hasn't already been said? A legend.
“He was a legend already and that legendary status became bigger tonight,” said Pep.
“I think he is one of he most incredible players I have seen in this league.
“I think he is proud of what he has achieved and we said congratulations in the locker room, because to score this amount of goals as a foreign player and score so many hat-tricks means that for many, many years you have done good things.
“To achieve this, he had to be consistent for many years and this is an incredible compliment for him.
“The most important thing is that he is an incredible person - you cannot score this many goals or break so many records if you are not somebody is happy to be with his team-mates.
“He has to always be fit to be at his best and he sometimes needs a bit of time after he has been injured or in pre-season, but he loves to play football and he is a guy who when he is in the final third always has a goal in his mind.”
City enjoy a six-day break before hosting Crystal Palace at the Etihad (3pm kick-off).