Guardiola tweaked his line-up with Gabriel Jesus, who had scored seven goals in his past three games, dropped to the bench in favour of Aguero, who made his first start since the 2-1 win over Liverpool on 3 January.
City should have been awarded a penalty in the 13th minute when Terence Kongolo went into the back of Sterling.
Danilo’s goal lifted a sloppy first half during which even Kevin de Bruyne, usually so assured in possession, was wasteful.
That was City’s 100th in all competitions this season – and they are the first side in Europe’s top five leagues (England, France, Germany, Italy and Spain) to reach the landmark.
Bar the two-goal burst, the visitors were nowhere near their attacking best, even when the two Silvas – Bernardo and David – came on in the second half.
Aguero barely threatened and only managed one shot, a half chance in the first half.
It was not the demolition many had predicted but ultimately it was mission accomplished for City, who have now scored 23 goals without reply and not conceded for 386 minutes.
Huddersfield, who are already out of the FA Cup, have a weekend off before hosting Everton in the league on 29 January.
City travel to Burton for the second leg of their Carabao Cup semi-final on Wednesday, leading 9-0 from the first game.
