The Blues had to come from behind to win, but goals from Kelechi Iheanacho secured a 5-1 victory and a tie with Middlesbrough a week on Saturday.
While City fielded a stronger starting XI than the one that began the initial tie at the John Smith’s Stadium, Huddersfield again began the game with numerous changes from the team that drew with Barnsley last weekend.
Though Yaya Toure and Aleks Kolarov were rested and Aleix Garcia was the starter who hasn’t had much game time this season.
Though the Blues would eventually wrestle control, it was the visitors who struck early on and would lead for much of the first half.
Leroy Sane rattled the foot of the post after just four minutes as the Blues looked to gain an early foothold, but Huddersfield did find the back of the net shortly after.
A well-worked move saw the ball fall to ex-City Academy graduate Harry Bunn who drilled a low shot underneath Claudio Bravo from 15 yards to send the 7,000 or so travelling fans wild
For the next 25 minutes, the Blues dominated without reward.
A couple of half-hearted penalty appeals were waved away by referee Paul Tierney until, finally, the Blues levelled.
It was Raheem Sterling who did the damage, teasing the Terriers; defence on the right-flank before playing a smart ball into the six-yard box for Sane to slot home.
It was the start of a frantic eight-minute spell that, by the end, saw City two goals in front - and it could have been more..
On 35 minutes, Nicolas Otamendi was bundled down in the box for what looked like a slightly fortuitous penalty award – duly dispatched by Aguero for his 21st goal from just 23 starts.
Moments later, Aguero won possession and raced towards goal only to see his placed shot strike the post, but it wasn't long before the home support were celebrating again as Aguero turned provider on 38 minutes, spotting compatriot Pablo Zabaleta lurking in the six-yard box who couldn’t miss from just a couple of yards out.
That equated to 12 goals in just 135 minutes of Etihad Stadium football on the back of the 5-3 against Monaco last time out - not bad value for money!
The second-half was a more relaxed affair with the visitors unable to create much of note and City taking their foot off the gas somewhat, but on 78 minutes, any lingering doubts about the final outcome were put to bed when Sterling's excellent cross was swept home by the excellent Aguero who looks back to his razor-sharp best.
Sub Kelechi Iheanacho put the icing on the cake in added time, tapping home Jesus Navas' cross to make it ten goals in two home games for the rampant Blues.
All in all, another entertaining night at the Etihad with the Blues' quest for silverware still firmly on track.
The award of the penalty kick with the scores level could be argued as the key moment in this game, but City's performance suggested the goals would come sooner or later
What it means…
City now travel to the Riverside Stadium on 11 March to face Middlesbrough in the FA Cup 6th round.
The Premier League game against Stoke that had been scheduled for that day will now be played on 8 March.
No doubt about it, Sergio is firing on all cylinders again. Two goals and an assist don't tell the whole story of the Argentine's night as he harried and ran all evening, never giving the visitors' defence a moment's peace.
City return to Premier League action on Sunday afternoon with a trip to bottom-of-the-table Sunderland.