Phil Werahiko's 'Tarf had Leinster lock Aidan Kearney sin-binned late on at Castle Avenue, but still held firm for their third bonus point in five outings.
That point leaves them one point clear of second-placed UCD in the standings.
Wing Mark Hewitt, centre Conor Mahony and pack heavyweights Dave Moore and Simon O'Donnell touched down for the home side, as Garryowen's late revival saw Gar Walshe and Conan Doyle cross the whitewash.
At Belfield, UCD took the Fogarty Cup honours as fly-half Eoghan Hickey again dictated matters in their 23-10 win over near neighbours Blackrock.
The 23-year-old converted Michael Hastings' first half try, and full-back Ross McCarron's effort - his second in two games - in the closing stages, completing a 13-point haul to see UCD remain the only unbeaten side in the top flight.
A jaded 'Rock mustered little in return as John Hearty's crossfield kick collect and dive over in the second half was their only bright spark.
Elsewhere, champions Shannon succumbed to a late sucker punch at Deramore Park, as Ulster flanker Matt Mustchin cross in the seventh minute of injury time, to hand Belfast Harlequins the spoils - 19-18.
Having lost prop Tony Buckley to a ruck infringement on 65 minutes, Shannon were left defending an 18-0 lead thanks to six David Delaney penalties.
However, with Ian Humphreys exposing their cover for 'Quins' first try two minutes later, and then WP Strauss converting that and Stuart Lamb's pushover effort on 83 minutes, the scene was set for Mustchin's late smash-and-grab effort.
Lansdowne plummeted to bottom spot as Richie Murphy inspired County Carlow to their first AIL win since March - 24-10 at headquarters.
Tim Bagg and Padraig Brennan touched down for the midlanders in either half.
Four David Connellan penalties saw Buccaneers up to third as they edged Dungannon 12-10, despite conceding a first-half Paul Magee try.
At Temple Hill, Galwegians earned their first league ever win over Cork Constitution as James Littleton and Tom Allen touched down in their 10-6 victory.
Allen's effort, after Con wing Cronan Healy had been sin-binned on 35 minutes for preventing Michael Roche take a quick tap, saw the visitors 10-6 in front at the break.
And despite losing Connacht tighthead prop Peter Bracken to a yellow card for kicking the ball away after the restart, Bernie Kelly's side hung on for their first win of the campaign.
Ulster fly-half Paddy Wallace marked his first game since damaging his ankle ligaments against Gloucester in October, by kicking two penalties and a conversion in new Ballymena coach Steph Nel's first win - a 23-22 defeat of Dublin University.
Jamie Heaslip, Martin Garvey, Matthew Darcy and all scored second half tries for the students, with a penalty try also netted, but they fell a Simon Mitchell conversion short of winning it at the death.
Results: Saturday December 18
Ballymena 23 Dublin University 22Belfast Harlequins 19 Shannon 18Buccaneers 12 Dungannon 10Clontarf 32 Garryowen 19Cork Con 6 GalwegiansLansdowne 10 County Carlow 24UCD 23 Blackrock 10
Barnhall 19 Terenure College 3
Ards 18 Clonakilty 26 Ballina 3 Corinthians 27 Banbridge 15 Bruff 16 Connemara 6 Instonians 9 Greystones 58 City of Derry 5 Skerries 27 Old Wesley 12 Suttonians 33 Wanderers 11