Manchester City are gunning for the quadruple this campaign and were almost caught in the ankles by Swansea but two goals from Sergio Aguero ensured that the Citizens came out tops.
The Liberty Stadium was rocking for about 60 minutes as Swansea came agonizingly close to a sporting success but it was substitute Sergio Aguero who put a stop to what would have been the most raucous of after-parties at the Stadium.
Both of the Argentine strikes, one from the penalty spot and the other a close range strike left Graham potter cursing at full time. The referee had been too harsh in giving away the first penalty which gave Aguero his first goal and had also turned deaf ears to pleas and cries for offside before the Argentine grabbed the winner.
Replays showed that the poacher was marginally offside but there were no VAR system in place to chop off the goal.
The pair of Riyad Mahrez and Leroy Sane had both lost glorious chances in the first few minutes and the Citizens were soon punished for it.
Swansea started out from the back with the goalkeeper giving the ball to Daniel James who must be praised for making Kyle Walker look a slouch. Dancing inside from the left he sends the ball to Celina who mustered all the energy he could to take it past Ederson.
Swansea fans were in dreamland after scoring their second against the visiting billonaires. Oh yes it was the second and the first had come from a Grimes penalty.
Guardiola bathed in fury sent in the attacking pair of Raheem Sterling and Sergio Aguero. The Argentinian caused some havoc few minutes after his introduction with his deflected strike bouncing into the path of Bernardo Silva who rifled home.
The Argentinian then went on to cause a devastating blow to the hosts with two goals to send Manchester City to the second round of the competition.