Liverpool's defence of the Carabao Cup began the way it was won with a penalty shoot-out victory in which goalkeeper Caoimhin Kelleher played a pivotal role.The Republic of Ireland international, playing his first game since scoring the winning spot-kick against Chelsea at Wembley in February, saved three Derby penalties as Jurgen Klopp’s untried side scraped past their League One opponents after a goalless draw.Harvey Elliott, introduced as a 65th-minute substitute along with Roberto Firmino and Darwin Nunez, scored the decisive kick as the disappointing hosts won 3-2 in the shoot-out.That it had reached that point was perhaps no surprise as Liverpool, who registered 11 changes from Sunday’s win over Tottenham, have not won a League Cup tie in normal time at Anfield since a 2-0 victory over Leeds in November 2016.Full debuts were handed to summer signing Calvin Ramsay (19), 17-year-old Bobby Clark – son of former Newcastle midfielder Lee – 18-year-olds Stefan Bajcetic and Melkamu Frauendorf and Layton Stewart (20).The five other senior outfield players had made just 25 starts between them this season and Joe Gomez accounted for 11 of those.Derby, 46 places below their hosts, knew their best chance was to frustrate and hope to take an opportunity when it came so when Liverpool entered their half they dropped into a back five, sometimes six, and the inexperienced midfield and forward line struggled to come up with a solution.In truth Liverpool looked like they were treading water until the introduction of the three senior players off the bench with 25 minutes to go.Half-chances came and went as Alex Oxlade-Chamberlain volleyed narrowly wide after Craig Forsyth only half-cleared a corner with his head, Stewart sliced over