Shannon remain in second place following their narrow 7-6 away win over Ballymena. Stephen Kelly scored a first half try for the Limerick side and Tadgh Bennett converted.
Garryowen remain in third place after their 20-13 win over Young Munster at Dooradoyle to remain in third place.
Two superb first half tries helped Garryowen into a 17-3 interval lead and the home club went on to earn the bragging rights against their great local rivals who will be happy enough to have got away with a bonus point.
The first try was a superb effort by Kevin Hartigan after a great run by Diarmuid McCarthy who was a member of the Castletroy College team who won the Munster schools cup for the first time last season. Lorcan Burke scored the second try which was also well executed. Conor Kilroy converted both tries and also kicked a penalty to leave it 17-3 at the interval.
Matt Costelloe kicked the Young Munster penalty.
A game that looked to be fading out as a contest suddenly burst into life when persistent Young Munster pressure brought a penalty try which Mike Prendergast converted and he then had a penalty to leave only four points between them, but the ever dependable Kilroy landed another Garryowen penalty to seal the win.
Dolphin are back up to fifth in the Division One after their 29-11 victory over UCD at Musgrave Park. Paul Hurley scored two tries and Barry O'Mahony and Rory Kenneally got one each. Barry Keeshan kicked three conversions and a penalty. Noel Reid replied with four penalties for thh students.
UL Bohemian turned on the style at Annacotty and their 34-0 win, plus bonus point, will be a boost in their attempt to finish in the top eight while Terenure College look more doomed to relegation.
Back row forwards, Kieran Essex (8) and flanker Tommy Oâ00Donnell both scored two tries, one in each half, for the winners who led 15-0 at the interval.
Right wing Finbar Aherne had the third try just after the break. Cathal Sheridan kicked a penalty and converted one of the tries while Fergal Lawler converted the last two tries.
In the Second Division U.C.C. maintained their challenge with a 43-3 win over Clonakilty at the Mardyke. Scott Deasy was the studentsâ00 hero running in four tries with Brian Derham and Peter Shallow also crossing the line. Gavin Dunne kicked four conversions. Gary Cribb replied with a penalty for the West Cork side.
Bruffâ00s promotion bid received a set back at Donnybrook, when the Limerick side lost 8-3 to Bective Rangers. Dave Maw kicked a penalty for the visitors.
Thomond looked like creating an upset in their Division Two tie at Rosbrien, when they led Old Crescent 6-0 at the interval thanks to two penalties by Anthony Hartery.
Inspired by a superb display from fullback, Ray Moloney, Old Crescent dominated the second half but will be disappointed not to have garnered a crucial bonus point.
Moloney flew in for two tries and Brian Oâ00Shea had another while he also landed a penalty and two conversions. Mark Woods also kicked a conversion for the winners.
Highfield made the long trek North and defeated Belfast harlequins 16-10. Nick Wakley was the â00Fields hero scoring a try conversion and two penalties. Conor Quaid added a drop goal.
In the Third Division Midleton maintained their challenge with a 28-11 home win over Naas but will be disappointed that they failed to pick up a crucial bonus point. Two tries from Junior Sifa and a conversion and penalty from Jeff Hitchmough had the home side 15-8 ahead at the interval. Brian Gill added a third try after the break and Hitchmough added a conversion and two penalties.
Nenagh Ormond maintained their recent good run with a 15-9 away win over Connemara. Gerard Hermes and James Kingston scored tries for the Tipperary side and John Lillis kicked a conversion and penalty.
Sundayâ00s Wellâ00s hopes of moving away from relegation received a major set back at Musgrave Park when they lost to fellow strugglers Rainey Old Boys 19-8. Alan Hickey scored a try for the â00Well and Ian Oâ00Regan kicked a penalty as the Cork side led 8-0 at half time.
Waterpark received another drubbing away to Portadown when they lost 61-9. Brendan Walsh kicked three penalties for the visitors.
AIB League Division 1:Ballymena 6,Shannon 7;
Blackrock College 48,Galwegians 10;
Buccaneers 6,St. Mary's College 21;
Cork Constitution 17,Clontarf 13;
Dolphin 29,U.C.D. 12;
Garryowen 20,Young Munster 13;
Old Belvedere 5,Dungannon 6;
U.L. Bohemian 34,Terenure College 0;
Division 2:Ballynahinch 23,Dublin University 13;
Bective Rangers 8,Bruff 3;
Belfast Harlequins 8,Highfield 16;
Instonians 23,Malone 25;
Lansdowne 26,D.L.S.P. 8;
Old Crescent 24,Thomond 6;
U.C.C. 43,Clonakilty 3;
Wanderers 13,Greystones 18;
Division 3:Banbridge 23,Queens University 13;
Barnhall 10,Ards 13;
Connemara 9,Nenagh Ormond 15;
Corinthians 8,Co. Carlow 3;
Midleton 28,Naas 11;
Portadown 61,Waterpark 9;
Sunday's Well 8,Rainey Old Boys 19;
Suttonians 13,Old Wesley 30;