Blackrock College gained their second win of 2012 as they got the better of fellow strugglers Old Belvedere in a hard-fought game at Stradbrook.
With both sides needing to put a run together to avoid relegation, there was a huge amount on the line in this south Dublin derby.
'Belvo were boosted by the presence of Leinster's Leo Auva'a at number 8, but his influence was quelled as Blackrock, with captain Des Dillon and David Gannon impressing up front, swept ahead.
Darragh Fitzpatrick continued his good scoring form by kicking the hosts ahead before flanker Michael McKeever broke through for an unconverted try.
Having lost their last five league games, 'Belvo needed some inspiration and they got off the mark before half-time thanks to a brace of penalties from full-back Eamonn Fitzgerald.
In a tense, turgid second half, a lone penalty from Fitzpatrick was the only score until the 'Rock out-half glided through for a superbly-taken converted try.
At 18-6 down, the game was out of 'Belvo's reach in the windy conditions but they did notch a late consolation try through Auva'a, with the losing bonus point leaving them seven adrift of 'Rock at the foot of the Division 1A table.
Referee: Peter Fitzgibbon (IRFU)