Peter Hutton headed Derry ahead just before half-time

The Candystripes went ahead just before half-time when skipper Peter Hutton headed in from close-range.

Gareth McGlynn notched number two six minutes after the break with a volley and Mark Farren quickly made it 3-0.

Shay Zeller was on target for First Division County on 63 minutes but Derry progressed to the quarter-finals.

So League Cup finalists Derry stay in with a chance of a remarkable treble.

In Stephen Kenny's first full season in charge their fortunes have been transformed after several battles against relegation.

Hutton's brave header on 45 minutes put the Candystripes on the victory trail, the home captain thundering into the danger area.

Two goals in four minutes effectively sealed the third round victory for the Premier Division title-chasers.

McGlynn's fine left-foot finish was followed by a third goal from top scorer Farren.

He blasted in after McGlynn had chested down a cross from former Cork City striker Stephen O'Flynn.

Zeller's goal caught the Derry defence off guard but City went through comfortably.