Three penalties from Gerry Hurley helped Cork Constitution to a 9-8 win over Clontarf at Castle Avenue.
Garryowen launched their bid to remain one of only two clubs never to have been out of the top grade with their first win of the season at Dooradoyle. Richie Lobb landed three penalties for Ballynahinch, one from inside his own half five minutes into the second half to make it 9-0 and matters look glum for Garryowen.
But tries by Harry McNulty and Anthony Kavanagh, and a two penalties and a conversion by Jamie Gavin sparked celebrations for the home side.
In Division 1B U.L. Bohemian promotion prospects received a major setback at Deramore Park when they went down 20-0 to Belfast Harlequins.
In Division 2A promotion hopefuls Queens University and City of Derry were beaten by Munster sides.
Second placed Queens University lost away to Cashel 16-3 while struggling Highfield travelled to Judges Road and defeated City of Derry 17-14 to move out of the relegation zone.
Old Crescent still remain second last in the table after their 15-7 win over Naas at Rosbrien. Garth Quinn- McDonogh scored a try, conversion and a penalty for the winners and Sean Monaghan also scored a try.
In Division 2B Nenagh Ormond remain unbeaten after their 20-10 away win over Boyne.
Thomond scored seven tries in their 39-0 home win over bottom side Suttonians. Diarmuid O'Neill scored two tries for the winners and Dean O'Brien, Wayne Mullaney, Kevin O'Mahony, Leonard Slattery and Diarmuid Ryan all scored tries and Dermot Fitzgerald kicked two conversions.
Sundays Well had a great win over Sligo winning 17-11. The 'Well scores all came in the opening ten minutes a try from Lar Coughlan, a penalty try and a penalty and two conversions from Shane O'Riordan.
Midleton lost 13-0 away to Skerries all the scores coming at the start of the second half in what was a very disciplined performance by the East Cork side
Ulster Bank League Division 1A: Clontarf 8, Cork Constitution 9;
Dolphin v Young Munster postponed;
Garryowen 18, Ballynahinch 9;
Old Belvedere 19, Lansdowne 13;
St. Mary's College 26, U.C.D. 15;
Division 1B: Belfast Harlequins 20, U.L. Bohemian 0;
Dublin University 25, Dungannon 19;
Malone 13, Buccaneers 8;
Shannon v Galway Corinthians postponed;
Terenure College 20, Blackrock College 8;
Division 2A: Bruff v Banbridge postponed;
Cashel 16, Queens University 3;
City of Derry 14, Highfield 17;
N.U.I.M. Barnhall 15, Bective Rangers 13;
Old Crescent 15, Naas 7;
Old Wesley v Rainey Old Boys Postponed
Seapoint 0, Galwegians 5;
U.C.C. v Ballymena postponed;
Division 2B: Boyne 10, Nenagh Ormond 20;
Greystones 21, City of Armagh 5;
Instonians v D.L.S.P. postponed;
Navan 17, Ards 10;
Richmond v Tullamore postponed;
Skerries 13, Midleton 0;
Sligo 11, Sunday's Well 17;
Thomond 39, Suttonians 0;