This win lifts Garryowen out of the relegation zone leaving Clontarf in relegation trouble three points behind them.
The Limerick side did all the damage in the opening half when Mick Sherry put them ahead with a try after eight minutes which Conor Murray converted. Murray extended that lead to 13-0 by half time with penalties on 19 and 31 minutes.
Rory Kenneally opened Dolphin's account with a try and a penalty try mid way through the second half which Barry Keeshan converted left a point between the sides.
In a grand stand finish Dolphin were camped on the Garryowen line but solid defending by the home side kept them out and the nearest the Cork side came to taking the lead were two drop goal efforts by skipper Keeshan that were off target.
Despite beating Thomond 14-13 at The Vale, Clonakilty are still in second last place in Division Two, but level on points with Highfield, a side they face at home next Saturday in a crucial tie.
A try by Dean Landy and three penalties by Kurt Morath had the home side 14-0 in front by half time. Thomond hit back with a try by Darragh O'Neill and a conversion and two penalties by Ger Finnucane, but the home side hung on for the four vital points.
Richmond who collected maximum points from their home tie with Thurles in the Munster Junior League after their 29-7 victory, are level on points with Tralee in Division One, but lead on the head to head result.
With two games remaining against bottom side St. Senan's at home and Ballincollig away, Richmond must now be strong favourites to win the trophy for the second time, there last success being in 1996.
A Wayne Murphy penalty gave Richmond a 3-0 interval lead and second half tries by Michael Kelleher, Jeff McNamara, Patrick McNamara and Brian Begley secured the bonus point. Murphy converted three of the tries. Brian Lyons replied with a try for Thurles, which Aidan O'Dwyer converted.
Tralee were fortunate to see off the challenge of Crosshaven as they came out on top 7-3 with all the scores coming in the opening half. The Kerry side were awarded a penalty try which Chris Dermody converted and Ger Fitzgerald replied with a penalty for the visitors.
Defending champions Cashel are three points behind the leaders after their 18-12 away win over Kilfeacle. A try by Daragh O'Brian and a conversion and two penalties by Pat O'Connor had Cashel 13-3 ahead at the interval. Max Nannini added a second try for Cashel and Kilfeacle replied with tries from Jack O'Sullivan and Shane Luby. The latter also kicked a penalty in the opening half.
Cobh Pirates defeated St. Senan's 17-3 to leave the Clare side at the foot of the table and almost certain to be relegated after one season in the top flight. John Fotu, Thomas Keaveny and Mark Chandler were try scorers for the Pirates. Joe Hoyne kicked a penalty and Denis Collins replied with a penalty for the visitors.
Ballincollig eased their relegation worries with a 13-9 home win over Skibbereen. The winners who led 5-3 at half time had tries from Dave Power and Padraig Bohane. Brian O'Keeffe kicked a penalty and Skibbereen replied with three penalties from Mark Kingston.
Clonmel continued their recent good run with an 18-13 home victory over Waterpark. The sides were level 3-3 at half time with Brendan Walsh opening the scoring for Waterpark and Morgan Lyons replying for the home side. Six minutes into the second half Clonmel took the lead with a try from Paddy Long after great work by John "Logger" Long and scrum half John Long. Morgan Lyons extended that lead to 18-3 with a try, conversion and penalty. Two late tries in the final five minutes by Joe McSweeney and Gerry Miller earned the visitors a bonus point.
Clanwilliam have extended their lead at the top of the Second Division to two points following their 16-12 away victory over Ennis. A try by Vivion Grisewood and a conversion and penalty by Willie Dwyer had the Tipperary side 10-6 ahead at half time. Dwyer added two further penalties after the break and Bryan Murphy kicked four penalties for the Clare side.
Galbally collected maximum points with a 27-7 away win over Bandon and moved into second place. James Taylor, James Stapleton, Jamie Hedigan and Kevin Casey scored tries for Galbally and Karl Bourke kicked a penalty and two conversions. Brian Galvin replied with a try for Bandon and Eanna Kelleher converted.
Old Christians are now three points behind the leaders with a game in hand after they played a 16-16 draw with Kinsale at Rathcooney. Kinsale led 13-3 at half time with a try from Edouard Lemaire and a conversion and two penalties by Peter Murphy to an Aidan Tobin penalty. A try by Paul McGrath and a conversion and penalty by Tobin levelled the scores. Murphy restored Kinsale's lead with a penalty but another Tobin penalty meant the points were shared.
Newcastle West traveled to Newport and defeated the home side 15-9 in an ill tempered game that saw seven yellow cards being shown. The visitors led 9-3 at half time with Tommy Kelleher kicking five penalties for the winners and Philip O'Brien replied with three penalties for the home side.
St. Mary's collected their first win of the season with a 25-20 home win over Muskerry. This result lifts the Corbally side off the foot of the table and level on points with Ennis.
Dan Doran, Eugene Payne and Barry Gibbons were try scorers for the Saints and Gibbons kicked two conversions and two penalties. Eamon O'Mahony, JJ Herlihy and Jaydee Meyer replied with tries for Muskerry and Dave Foley converted two of the tries.
Youghal are now at the foot of the table after Kanturk gained revenge for their Cup exit at Youghal last week when they traveled to the East Cork venue for a second successive week and recorded a 19-6 victory. Daniel O'Callaghan scored the game's only try for the Duhallow side and Dara Meade kicked a conversion and four penalties. Jonathon Ormond replied with two penalties for the home side.
Castleisland extended their lead at the top of Section A of the Third Division to twenty points after their 52-10 away win over Kilrush. Seamus Moynihan scored three tries for the winners, Daniel Walsh two and Mike Cronin, Bill Horgan and Kevin Ryan one apiece. Mark Connolly converted seven of the tries and also added a penalty.
Killarney remain in second place after their 17-10 away win over Scariff. Ger Moynihan, Brian O'Sullivan and Brian O'Leary were try scorers for the Kerry side and Mike Nash kicked a conversion.
Killorglin made it three wins in a row with a 12-10 home win over Corca Dhuibhne. John Ahern kicked four penalties for the winners and Johnny Curran replied with a try, conversion and penalty for the West Kerry Gaeltacht side.
Abbeyfeale and Presentation shared the spoils at the West Limerick venue after they played a 10-10 draw. Michael English scored a try for the West Limerick side and Robert Brown converted. David Collins earned the home side a draw with a penalty after Presentation led 10-7 with a try from Shane O'Brien and a conversion and penalty by Mark Phair.
In Section B: Mallow have joined Charleville at the top of the table, after they defeated their North Cork rivals 14-11. Sam Holt scored two tries for the home side and Brian Morris converted. James Leahy replied with a try for Charleville and Frankie Holly kicked two penalties.
Fermoy kept their promotion hopes alive with a 10-6 away win over Douglas. A penalty try converted by Cathal O'Keeffe had Fermoy 7-6 ahead at half time. Andy Larkin kicked two penalties for the home side. An O'Keeffe penalty after the break ensured Fermoy collected the points.
Two tries by Eoin Murnane and one by Andrew Quinlan was not enough for Shandon to get their first win as they lost away to Carrick-on-Suir 23-17. Conor Buckley kicked a conversion for the visitors. James Wallace and John O'Keeffe were try scorers for Carrick' and Michael Cronin converted both and also added three penalties.
Waterford City defeated Dungarvan 25-13 with tries from Sean O'Mahony and John Doran. Aaron Foskin kicked five penalties. Joey Lawlor and David O'Riordan scored tries for Dungarvan and Michael Irwin added a penalty.
Cork Constitution came from 8-0 down to beat Sunday's Well 15-8 at Temple Hill in the Munster Seconds League South section. A try by John Verling and a Colin Corkery penalty put the visitors into an 8-0 lead. An Alan Ross try converted by Michael Keyes left the home side trailing by a point at the break. Keyes added a penalty to put Con' ahead and Tim Dukelow scored a try.
In the second phase of the Junior Two League South, Dunmanway defeated Old Christians 8-3. Gordon Brett scored a try for the winners and Mark Kingston kicked a penalty.
Cobh Pirates proved too strong for Listowel running in seven tries in their 44-0 home victory. James Murphy scored three tries, Gary price two and Liam Greaney one apiece. Tadgh Hawes kicked three conversions and a penalty.
Cork Constitution had to battle hard for their 21-18 away win over Clonakilty in the Mick Barry Cup. Tadgh Buckley, Ronan O'Sullivan and Eddie Quinn scored tries for the winners and Simon Barry kicked three conversions.
Sunday's Well got of to a winning start in the George O'Connell Cup with a 22-0 away win over Killarney. Joe O'Donovan, Eric Broderick and John Kelly scored tries for the visitors and Harry Lane kicked two conversions and a penalty.
AIB League Division 1A:Garryowen 13,Dolphin 12;
Division 2:Clonakilty 14,Thomond 13;
ODM Munster Senior Cup Semi Final:Shannon v U.C.C. OFF;
Munster Junior League Division 1:Ballincollig 13,Skibbereen 9;
Clonmel 18,Waterpark 13;
Cobh Pirates 17,St. Senan's 3;
Kilfeacle 12,Cashel 18;
Richmond 29,Thurles 7;
Tralee 7,Crosshaven 3;
Division 2:Bandon 7,Galbally 27;
Ennis 12,Clanwilliam 16;
Newport 9,Newcastle West 15;
Old Christians 16,Kinsale 16;
St Mary's 25,Muskerry 20;
Youghal 6,Kanturk 19;
Division 3 Section A:Abbeyfeale 10,Presentation 10;
Corca Dhuibhne 10,Killorglin 12;
Kilrush 10,Castleisland 52;
Scariff 10,Killarney 17;
Section B:Carrick-on-Suir 23,Shandon 17;
Douglas 6,Fermoy 10;
Mallow 14,Charleville 11;
Waterford City 25,Dungarvan 13;
Munster Seconds League South:Cork Constitution 15,Sunday's Well 8;
Gleeson League:Bruff ,Cashel ;
Garryowen ,Shannon ;
Kilfeacle ,Galbally ;
Young Munster ,Richmond ;
Junior 2 League South Group A:Ballincollig 6,Skibbereen 3;
Tralee 11,Dolphin 0;
Group B:Cobh Pirates 44,Listowel 0;
Dunmanway 8,Old Christians 3;
Mick Barry Cup Group A:Muskerry 14,Bandon 0;
Group B:Clonakilty 18,Cork Constitution 21;
George O'Connell Cup:Bantry Bay 22,Kinsale 15;
Killarney 0,Sunday's Well 22;
Junior 3 League South Group A:Ballincollig 22,Youghal 8;
Under 21 South Western Conference Division 1A:Shannon 16,Garryowen 11;
U.C.C. 36,Bruff 6;
U.L. Bohemian 18,N.U.I.G. 3;
Division 1B:Buccaneers 18,Corinthians 17;
Highfield ,Galwegians ;
Waterpark 12,Young Munster 10;
Division 2:Old Crescent ,Cashel ;
Casey Cup:Dungarvan 11,Waterford City 0;
Avonmore Milk Munster Under 17 League Section C:Bandon 3,Garryowen 9;
South Under 19 Development League:Bandon 16,Youghal 12;
Douglas 15,Dunmanway 0;
South Under 17 League Phase 2 Section A:Douglas 17,Highfield 19;
Mallow 22,Cork Constitution 22;
Section B:P.B.C. 26,Muskerry 7;
Midleton 25,Kinsale 5;
Sunday's Well 14,Cobh Pirates 5;
Section C:Clonakilty 12,Crosshaven 11;
South Under 15 League Section 1:Charleville 0,Sunday's Well 15;
Muskerry 22,Cork Constitution 38;
Section 2:Clonakilty 12,Highfield 12;
Munster Women's Cup Group 1:Nenagh Ormond 12,Tralee 7;
Group 2:Youghal 0,Highfield 55;
Under 19 Girls Development Cup: North Cork 55,Crossfield 15;