And if the truth be told, Stephen Kenny's men should have defeated near-neighbours, Finn Harps, by an even great margin had they taken advantage of the opportunities created.
With both teams making five changes from last Friday night's league games, it was Derry who bossed the ball throughout but, as has been the case over recent weeks, the 'Candy Stripes' frustrated in front of goal during the opening half an hour.
Deadlock was finally broken in the 31st minute when Harps full-back, Shaun Holmes lost possession to the lively Kevin McHugh and his low inswinging centre saw the advancing Conor Sammon bundle the ball home from close range.
After the break the home side maintained their superiority and they doubled their lead in the 48th minute.
Sammon sent McGinn clear on the right and the winger crashed a superb shot to the net from 20 yards to record his first goal for Derry City since his move from Dungannon.
And Derry basically ended the game as a contest in the 57th minute when Sammon netted his second of the night having been presented with an easy tap-in when inside the six yards box.
Derry City – Doherty; Deery (Sharkey, 78 mins.), McChrystal, McCallion, Callaghan; McGinn, McGlynn (Farren, 82 mins.), Molloy (Higgins, 68 mins.), Morrison; McHugh, Sammon.
Finn Harps – Cullen; Roddy, Boyle, Mukendi, Holmes (Gallagher, 72 mins.); Gill, McGowan, Shields (Brolly, 78 mins.), Williams; Ramsey (Breen, 46 mins.), Gethins.
Referee: R. Winters (Wicklow).