Most of the drama was reserved for Parnell Park as Castleknock edged Plunketts 2-18 to 2-15 after extra-time.
Plunketts, who defeated Ballyboden St Enda’s in the opening round, started off brightly and enjoyed a 0-7 to 0-4 interval lead following points from Alan Brogan, Garreth Smith and Bernard Brogan.
Their position improved within six minutes of the resumption as Niall Walsh netted from Alan Brogan’s pass but Castleknock struck back with Ciarán Kilkenny finding the net in the 38th minute.
Their momentum was maintained as Shane Lyons was adjudged to have fouled Kilkenny with Seamus O’Carroll converting the resultant penalty.
Alan Brogan’s goal 11 minutes from time looked to have secured his side’s progress but O’Carroll kicked four late frees to confirm extra-time on a 2-11 apiece scoreline.
Kilkenny added two points early on and O’Carroll’s trio of frees late on was just reward for last year’s beaten finalists.
The first leg of the double-header in Donnycarney saw St Brigid’s defeat Thomas Davis by 0-14 to 1-8.
Ciaran Farrelly scored an early goal for Thomas Davis but they failed to build on the platform as they trailed by 0-8 to 1-3 by the interval.
With Cian Mullins a towering presence at midfield, the 2011 winners pulled away with Philly Ryan, Lorcan McCarthy and John O’Loughlin all scoring three points over the hour.
Across the city in O’Toole Park, Ballymun Kickhams confirmed their tag of favourites by hammering St Mary’s 8-18 to 0-2.
Dean Rock scored 2-7 for the winners with Carl Keely, Colm Hulton, Jason Whelan, Conor Kavanagh and Kevin Leahy also among the goals for Kickhams.