Gael Clichy scored the opening goal three minutes after the break and a first professional goal for Aleix Garcia on 67 made it nine wins from nine games for Pep Guardiola.
City will face Manchester United in the fourth round of the competition at Old Trafford.
What happened
City created the first meaningful chance of the game on 12 minutes when Angelino swivelled and volleyed Pablo Zabaleta’s pull-back from the right wing, just missing the bottom corner with an effort which had wrong-footed Kristoffer Nordfeldt in the Swansea goal.
City, understandably given the sheer volume of changes, lacked a little of the sharpness we’ve seen in their perfect winning start to the season but the away side were very nearly ahead on 33 minutes when Mike van der Hoorn would have turned a Garcia cross into his own net but for Nordfeldt’s fine save.
The holders improved vastly in the closing minutes of the first period with Kelechi Iheanacho and Jesus Navas both having half chances as Garcia started to really impress with his vision and brave passing through the lines.
Goalless it was at the break but not for long… three minutes after the restart, Clichy scored his second goal for the Club, putting the finishing touches on a sweeping team move which Gael had played in an integral role in, even before his right-footed (!) strike.
Kevin De Bruyne entered the game with more than half an hour remaining but it was 19-year old Garcia who capped his fine performance with a goal, sidefooting in a Navas pull-back on 67 minutes to make sure of his side’s place in the fourth round.
With passage secured to the next round, Guardiola also handed Brahim Diaz his first-team debut with ten minutes to go but Swansea struck the game’s third goal, halving the deficit in stoppage-time through Sigurdsson.
Key Moment
Gael doesn’t get many and the finish may have been aided by a deflection but the build-up to the goal which broke the deadlock was pure Guardiola.
Elegant, one-touch passing took City from Caballero to Clichy (via Stones, Kompany, Sane, Gael himself and Angelino) before the French full-back pulled the trigger and saw his shot loop over Nordfeldt.
Beautiful, devastating football.
Man of the Match
Aleix Garcia
It was a night for surprise goalscorers at the Liberty Stadium but Aleix Garcia’s first for City was a just reward for a hugely promising display from the 19-year old.
Completely undaunted by the fact that this was just his second start for the team he joined in 2015, the Ulldecona-born midfielder asked questions of the home defence all evening long with his clever movement and intricate passing.
One of five players promoted to the first-team squad from the EDS by Pep this year, Aleix served notice on his potential and was a shoe-in for our Man of the Match award.
Photo of the Match
What it means
City’s reward for their victory over Swansea will be a fourth round clash against Manchester United at Old Trafford.
The match will be played on 25 or 26 October after United knocked out Northampton Town with a 3-1 win.
How they lined up
Pep Guardiola made nine changes to the team which beat Bournemouth 4-0 on Saturday, handing Kompany his first start for four months although the skipper appeared to walk off the pitch and down the tunnel in stoppage-time before the game was over.
Elsewhere, Leroy Sane earned his first start for the Blues, while Angelino and Garcia both made their second starts for the Club in attacking midfield roles and the hero of last season’s final, Caballero, started in between the sticks.
Clichy and Iheanacho were the two players who retained their places from the weekend, while there was a young bench, featuring Angus Gunn, Tosin Adarabioyo and Pablo Maffeo, as well as Brahim, who came on for his debut at the tender age of 17.
Stats and Milestones
City have now won their opening nine games of the season
Gael Clichy scored his second goal for the club since he joined in 2011 – his last was against Southampton in 2014/15.
Brahim Diaz made his professional debut for City
This was the first of two meetings with Swansea at the Liberty Stadium inside a week
Pep Guardiola took charge of his first game in the Football League Cup
Vincent Kompany made his first City appearance since 4 May 2016
Leroy Sane earned his first start for the club since joining from Schalke in the summer
Angelino and Aleix Garcia both made their first League Cup starts and second competitive starts overall
City are unbeaten in the League Cup since 29 October 2014
