Cork Con are still well in contention for a play-off spot while Dolphin have given themselves a fighting chance of staying up in the top flight of the Ulster Bank League.
There are now just two rounds remaining, with Lansdowne and Terenure already confirmed as the two home semi-finalists - Clontarf are five points clear in third and Con are fourth. They will fight it out with five teams for the remaining slot.
Con are only five points clear of ninth-placed St Mary's - Con lost 27-20 at Lansdowne in Round 16 but their losing bonus meant they moved ahead of Ballynahinch. Darren Sweetnam crossed twice for Tom Tierney's men.
Young Munster are still in the race after a 20-17 win over UCD - Shane O'Leary got a try to add to their penalty try.
Dolphin produced one of the performances of the weekend to beat reigning champions Clontarf 24-22 but they are seven points behind St Mary's.
In Division 1B second-placed Garryowen cannot afford a slip-up if they are to push league leaders Galwegians all the way - they play each other in the final round. Elsewhere Shannon look to be safe while UL Bohemians must keep winning to ensure they remain in 1B next season.
In 2A, fifth-placed Cashel are the only likely Munster candidate for promotion while in 2B Highfield are champions - they beat Richmond 31-6 to ensure they couldn't be caught at the top.