Galwegians slipped to fifth in the table after they lost at Crowley Park to the Dan Van Zyl inspired Co Carlow who started the day second from bottom. Van Zyl scored a try as did Mark Buckley and Russel Armstrong.
In Ericsson Park, two late tries from John Farrell and Michael Carroll gave the visitors victory on their first ever visit to this venue.
Ballymena dominated their tie with Belfast Harlequins from start to finish, ending up 29-7 victors, their out-half Dirky Strydom acounting for 19 of his side's total.
In Thomond Park, Clontarf gained a degree of revenge for their semi-final defeat last season, when a 79th minute Niall O'Brien try helped them to a 17-11 win after a fairly dull encounter.
UCD lifted themselves off the bottom of the table after beating Dungannon 21-19, their winner - an Eoghan Hickey drop-goal - coming in the closing stages.
Man of the Match Matt Leek was the inspiration behind Lansdowne's 27-17 win over Cork Constitution at Temple Hill. Leek scored a try, a conversion, a drop-goal and four penalties as Lansdowne won for the first time at the home side's ground.
A young St Mary's side looked certain to record their second win of the league when they led Garryowen 20-17 as the full time whistle was about to be sounded. Then however, Mary's were penalised on their own 22 for handling and Billy Treacy stepped up to kick the equalising penalty.
A fifth consecutive defeat, this time at the hands of fellow strugglers UL Bohemians, leaves Terenure College frimly rooted to the bottom of the table. They lost 15-13, in Lakelands, all the scores coming in the first half when Bohs had tries from Keith Matthews and Aiden O'Gorman.