Clontarf will face Buccaneers at home in the AIL Division One play-off semi-finals after the Castle Avenue club secured top spot in the league thanks to a resounding 80-10 win over St Mary's this afternoon.
The other semi-final will be contested between Lansdowne and Ballymena with the Dublin club enjoying home advantage.
Clontarf brought the curtain down on an outstanding league campaign with their 13th win to breach 60 points. Knowing victory would guarantee them first place and a home semi-final draw, Andre Bester's charges didn't disappoint as they steamrollered a St Mary's side going through the end of season motions.
Out-half Matt Leek proved the Lansdowne hero when his drop-goal at the death earned all five points against Galwegians and a home semi-final to boot.
Galwegians, themselves harbouring outside ambitions of claiming fourth spot, raced into an early 10-0 lead. But Harry William's Lansdowne were shaken into action and three first half tries helped them to a 19-17 interval lead.
The visitors again made the early running in the second period for a 31-19 lead but Lansdowne fought back once more to level the scores before Leek's intervention with the last kick of the game to run out 34-31 victors.
At a blustery Ericsson Park, Buccaneers earned the solitary point they required to secure a play-off berth thanks to a last minute try from Justin Meagher. Their match against Ballymena finished all-square on 28-28.
At Deramore, Belfast Harlequins tilt at a play-off spot foundered against the challenge of a determined Shannon side. Trailing 14-0 at half-time, Harlequins fought back as they attempted to overhaul Buccaneers in fourth position.
But having claimed a 19-17 lead entering injury-time, the home side's line was breached by James Blaney and the visitors claimed a 24-19 victory.
Meanwhile, UL Bohemians will join Terenure in Division Two next season after a 41-29 defeat at the hands of Co Carlow condemned them to relegation.
Elsewhere, Dolphin have earned promotion to the top flight, after a five-year absence, thanks to 38-6 win over Malone.
AIL Division One results
Belfast Harlequins 19-24 Shannon
Blackrock Col 19-27 Garryowen
Buccaneers 28-28 Ballymena
Clontarf 80-10 St Mary's Col
Dungannon 56-33 Cork Constitution
Lansdowne 34-31 Galwegians
Terenure Col 25-26 UCD
UL Bohemians 29-41 Co Carlow