Pep Guardiola hailed an "incredible" professional debut from Eric Garcia after the 17-year-old starred in Manchester City's Carabao Cup quarter-final triumph at Leicester City.
As they did at the same stage in last season's competition, the holders needed penalties to progress after a 1-1 draw at the King Power Stadium.
Kevin De Bruyne scored a spectacular opener but Marc Albrighton hauled the hosts level, only to see penalty misses from team-mates Christian Fuchs, James Maddison and Caglar Soyuncu help Guardiola's men through.
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During the 90 minutes, former Barcelona youth graduate Garcia caught the eye at the heart of defence alongside Nicolas Otamendi and Guardiola suggested the teenager would have featured sooner if not for an injury setback earlier this season.