Mullinahone were without the suspended Eoin Kelly but Curran scored 2-6 of his side’s tally, his other goal coming from a penalty in the 26th minute which helped Mullinahone lead 1-6 to 0-8 at the break.
Depleted Nenagh looked to have won it when Mikey Heffernan - who hit 11 points - nailed a free in the 63rd minute for the lead, but Mullinahone’s Donal Cody was fouled a minute later, and Curran slapped home the winning penalty.
Borrisoleigh survived a late rally from Roscrea to secure the draw (0-16 to 2-10) they needed to qualify as runners-up in their group.
Without the injured Brendan Maher and Paddy Stapleton Borris led 0-10 to 1-5 at half-time and were still clear with time running out. But Shane Fletcher’s late goal earned a point for Roscrea.
Champions Sarsfields kept their unbeaten record intact with a third successive win, defeating Éire Óg, Anacarty 0-20 to 0-15. Sars coasted 0-9 to 0-2 ahead after 15 minutes and were 0-12 to 0-7 to the good at the break.
But Éire Óg, with Conor O’Brien leading the way, were ahead going into the final quarter. However, Sarsfields showed their class with six unanswered points. Billy McCarthy, Padraic Maher, Pa Bourke and Michael Cahill were the key men.
Fancied Drom-Inch looked on course for victory when they led Killenaule by three points with time running out but Killenaule snatched a late draw to stay top of their group.
Unbeaten Clonoulty- Rossmore were comfortable 1-19 to 1-9 winners over Portroe to clinched their place in the knock-out stages. So too did Kildangan, also unbeaten after their 2-22 to 2-18 win over Templederry.
Veteran Pat Shortt scored three goals as Upperchurch-Drombane defeated J K Brackens 3-18 to 0-13.
Kilruane beat Lorrha 0-28 to 1-18, for their second win. Kilruane led 0-13 to 0-11 at the break, and despite a second half goal from Patrick ‘Bonnar’ Maher for Lorrha, Kilruane held on comfortably.
Burgess proved too good for Holycross-Ballycahill, winning 1-17 to 1-12. Stephen Murray scored 12 points for Burgess whose first-half goal came from Shane Maher. Jack Skehan had a late goal for Holycross.
Loughmore-Castleiney had much the better of Knockavilla Kickhams in the second- half to emerge victorious on a 0-28 to 2-12 scoreline.
Moycarkey-Borris defeated Moneygall 1-19 to 2-9, while Ballina and Ballingarry played a 0-11 each draw in their top of the table clash.