The visitors were the first on the score board following a Ronaldson penalty on the seventeenth minute but Dolphin retaliated immediately with a try from James Kiernan and Barry Keeshan added the extras.
Moments later a Craig Ronaldson interception set Lansdowne up for their first try as Ross McCarron touched down and Ronaldson converted. Five minutes later Kyle Tonetti burst through the home defence from the 22 and crossed the line for the Leinster side's second try of the afternoon.
The home supporters were not waiting long for a response as some fast hands between Munster pair Cian Bohane and Sean Dougall put Harry Fleming under the posts. A Barry Keeshan conversion and successful penalty kick on the thirty fourth minute sent Dolphin into the break with a 17-15 lead.
However, four penalties from the boot of Ronaldson in the second half put the league leaders ten points infront with twelve minutes remaining. Lansdowne were reduced to 14 men after Clive Ross received a yellow card for pulling Brian O' Callaghan down in the line out. Dolphin launched an unrelenting attack on the visitors in the final stages of the game and Barry Keeshan kicked a further penatly to narrow the gap to 20-27.
Dolphin asked questions of the Lansdowne defence and of their set piece when Munter Academy player Niall Scannell stole two line out balls just outside their 22 in the closing minutes of the game. When fellow Munster Academy player James Cronin crossed the whitewash it came down to the conversion to level the sides. But the attempt fell just wide of the posts to seal the four points for the table toppers.
Dolphin: Denis Hurley, James Kiernan, Harry Fleming, Cian Bohane, John Gleeson, Barry Keeshan, Brian Slater, James Cronin, Niall Scannell, Christy Condon, Chris Rowe, John Madigan, Rob O' Herlihy, Sean Dougall, Brian O' Callaghan Repalcements: John Leahy, Will Foley, Miah Cronin, Chris Bannon, Eamon Mills.
Lansdowne: Ross McCarron, Rob McCarhty, Kyle Tonetti, Mark Roche, Matt Healy, Craig Ronaldson, Paddy O' Driscoll, Jack O' Connell, Steve Collins, Martin Moore, Willie Earl, Mark Feeley, Clive Ross, Charlie Butterworth, Ron Boucher Replacements: Tyrone Moran, Richard Liddington, Dan Mannion, Marcus Walsh, Ferdia Doherty.
Elsewhere today, Young Munster moved within two points of second place Garryowen with an 10-8 victory and a game in hand after they were awarded a last minute penalty try away to Old Belvedere. The conversion from Shane O' Leary and a penalty from Brian Haugh was enough for Young Munster to close the gap on Garryowen after they were defeated at home by Cork Constitution.
Johnny Holland kicked all 21 points for Cork Constitution in their 21-18 victory over the Limerick side, despite tries from Conan Doyle, Ronan O' Mahony and eight points courtesy of Matthew Jervis. A losing bonus point was all that Garryowen had to show for their efforts, but indiscipline cost them and they will rue their missed chances.
Friday nights action saw Shannon claim a valuable bonus point victory at home to rivals U.L. Bohemian in only their second win of this league campaign. Their previous win also coming against U.L. Bohemian earlier in the season. Man of the match Tagdh Bennett scored two tries, converting one. Rob Guerin kicked a further nine points and tries from James Loxton and Munster's Luke O' Dea gave Shannon this much needed win which sees them jump witin two points of their opponents at the bottom end of the table.
While St. Mary's 19-17 win over Clontarf takes them four points clear of U.L. Bohemian into eigth place.
Cashel continued their good run in Division 2A with a 32-23 away win over Seapoint. Kevin Quinlan ran in three tries for the Tipperary side and Giles Boland also scored a try. Pat O'Connor kicked three conversions and two penalties.
Ulster Bank League Division 1A:
Clontarf 17 St. Mary's College 19
Dolphin 25 Lansdowne 27
Garryowen 18 Cork Constitution 21
Old Belvedere 8 Young Munster 10
Shannon 31 U.L. Bohemian 13
Belfast Harlequins 3 Ballynahinch 36
Bruff 3 U.C.D. 26
Buccaneers 36 Blackrock College 36
Dublin University 24 Dungannon 16
Malone 26 Ballymena 5
Old Crescent V Galwegians (Match Postponed)
Seapoint 23 Cashel 32