The Limerick city side made it five wins from five in the group stages of the county championship and therefore move directly into the semi-finals.
They will be joined in the last four by Doon.
The final round of group games confirmed the quarter-final line-up — 2012 county champions Kilmallock will play South Liberties, while the beaten finalists of the last two seasons Adare face 2011 finalists Ahane.
The relegation issue was also decided over the weekend with Granagh-Ballingarry and Knockainey confirmed to drop to the premier intermediate hurling championship.
Na Piarsaigh continued their unbeaten run with a 3-17 to 2-11 win over Ballybrown in the Gaelic Grounds. The champions were 2-9 to 2-5 ahead at half-time but were 1-3 to no score clear after three minutes.
Kevin Downes had the early goal for Na Piarsaigh but two goals from Alan O’Connor had Ballybrown level midway through the opening half.
Shane Dowling had the second Na Piarsaigh goal from a 21m free in the 22nd minute. Respective free-takers O’Connor and Dowling exchanged scores in the early minutes of the second half before Na Piarsaigh took over.
Downes, Alan and David Dempsey had points to open a 2-16 to 2-10 lead. Adrian Breen hit 1-1 in injury-time to complete the rout.
Unbeaten Doon were 2-18 to 2-17 winners over Murroe-Boher in Cappamore.
Kilmallock booked their place in the quarter-finals with a big 1-23 to 0-8 win over South Liberties in Bruff.
Despite the loss, South Liberties also progress to the knockout stages.
Kilmallock got off to a flyer when Graeme Mulcahy goaled in the opening quarter to give them a 1-5 to 0-2 lead. Points from Paudie O’Brien, Rob Egan and Benny Burke had them 1-14 to 0-4 ahead at half-time with South Liberties heavily relying on the frees of Ciaran Carberry.
Eight unanswered points in the early stages of the second half sealed a big Kilmallock win.
Adare ensured their quarter-final spot with a 2-20 to 3-11 win over Patrickswell in the Gaelic Grounds. They looked on course for an easy win when 0-8 to 0-3 clear at the end of the opening quarter, with Donnacha Sheehan and Lucas O’Brien on the scoresheet.
But then came a Diarmuid Byrnes goal for Patrickswell and the sides went in level at the break (0-10 to 1-7).
An O’Brien goal midway through the second half helped Adare into a 1-17 to 1-11 lead.
Thomas O’Brien hit back with a Patrickswell goal but then Mike Mackey netted to all but seal the win.
A 2-10 to 0-14 defeat to Effin saw Granagh-Ballingarry relegated.
A Hugh O’Neill goal had Effin up 1-7 to 0-7 at half-time. The all important second goal came in the final minutes when a long-range free from Effin goalkeeper James O’Leary went all the way to the net.