Starting in place of Pat Hoban, Danny Mullen found the net twice for the Candystripes
A double from Danny Mullen helped Derry City knock holders St Patrick's Athletic out of the FAI Cup at the second-round stage.
After the disappointment of their Uefa Conference League exit at the hands of Bruno Magpies on Thursday night, Ruaidhri Higgins' side looked flat in the early going but blew their visitors to the Brandywell away with a three-goal salvo in 15 second-half minutes.
Despite a missed penalty from Will Patching, Mullen's two goals put Derry in control before Michael Duffy made the tie safe with a little over 20 minutes remaining.
St Pat's, who continue to struggle despite the appointment of former Republic of Ireland boss Stephen Kenny in May, were deservedly beaten on the night despite starting the better of the sides.
In a first half of little incident, Derry keeper Brian Maher was forced into a fine one-handed save from Chris Forrester's strike but chances were largely few and far between.
The hosts, who offered their only real threat early on through set-pieces, did have a penalty appeal waved away after some wrestling in the box but failed to trouble Joseph Anang in the St Pat's goal.
Brian Maher made a brilliant save in an otherwise dull first half
But the Candystripes were a different team to start the second half.
Less than two minutes after the restart, they were awarded a penalty when Paul McMullan was adjudged to have been fouled just inside the box by Axel Sjoberg
Will Patching's spot kick was struck with little power, however, and Annang got down to his left to push the ball around the post.
Patching would produce a much better strike only moments later, this time his effort from the edge of the box was fizzed over the bar.
Less than five minutes after the penalty miss, Derry were ahead when Michael Duffy got to the by-line and his pullback was turned into the net by Mullen.
In a fine spell for the hosts, Adam O'Reilly looked set to double the advantage when collecting Mullen's pass in the box but Tom Grivosti threw his body in front of the ball to block the shot.
The reprieve was only temporary with Mullen powering a header home from the resulting corner.
Duffy was denied by Annang from point-blank range but the impressive winger would take his next chance, sliding the ball into the bottom corner after a threaded pass from O'Reilly to round out the scoring.
On his return to a Brandywell ground where he spent two separate spells as boss, Kenny will surely be especially disappointed by how few questions his side asked of Derry in an attempt to get back in the game with their defence of the trophy petering out across the game's final quarter.
