Leinster moved up to second in the PRO12 table after they battled past Ulster 19-6 at the RDS on Saturday.
Jordi Murphy's converted try and Jimmy Gopperth's penalty took Matt O'Connor's men into a 10-6 lead at the interval, while Paddy Jackson responded with two three-pointer for the visitors.
But it was the Dublin outfit which controlled the second half and three successive kicks from their fly-half sealed a vital win.
Despite their excellent European form, the hosts went into the game outside the PRO12 play-off positions in fifth with six wins from 10 games.
They immediately fell behind to their Irish rivals when Jackson kicked a penalty before Gopperth levelled matters with one of his own.
The match proved unsurprisingly tight throughout the opening period with bragging rights and a place in the top-four at stake.
It wasn't until the 34th minute when the next score was produced as Jackson was successful once again with the boot. However, with the half nearing its conclusion Ulster's Sean Doyle was sin-binned for a cynical infringement and the home side capitalised when Murphy touched down.
Leinster started the second period as they ended the first - on the front foot - and Gopperth extended their lead to seven points with half-an-hour remaining.
Although the Belfast-based outfit had fleeting moments of inspiration, mistakes often prevented them from creating concerted pressure. And with the hosts' fly-half punishing any Ulster indiscretion, they quickly found themselves 19-6 down thanks to successive penalties from the Kiwi.
The visitors put pressure on the home team's rearguard towards the end of the match but they couldn't find the decisive try which would secure a losing bonus-point.
Pen: Gopperth 4
Pen: Jackson 2
Leinster: 15 Zane Kirchner, 14 Dave Kearney, 13 Brendan Macken, 12 Noel Reid, 11 Luke Fitzgerald, 10 Jimmy Gopperth, 9 Isaac Boss, 8 Jordi Murphy, 7 Sean O'Brien, 6 Rhys Ruddock, 5 Mike McCarthy, 4 Leo Cullen, 3 Martin Moore, 2 Aaron Dundon, 1 Michael Bent.
Replacements: 16 James Tracy, 17 Mike Ross, 18 Jack O'Connell, 19 Tom Denton, 20 Dominic Ryan, 21 Luke McGrath, 22 Ian Madigan, 23 Darragh Fanning.
Ulster: 15 Ricky Andrew, 14 Andrew Trimble, 13 Darren Cave, 12 Luke Marshall, 11 Craig Gilroy, 10 Paddy Jackson, 9 Paul Marshall, 8 Roger Wilson, 7 Sean Doyle, 6 Robbie Diack, 5 Dan Tuohy, 4 Lewis Stevenson, 3 Declan Fitzpatrick, 2 Rob Herring, 1 Callum Black.
Replacements: 16 Niall Annett, 17 Tom Court, 18 Nicky Lutton, 19 Neil McComb, 20 Mike McComish, 21 Ruan Pienaar, 22 Jared Payne, 23 Michael Allen.
Referee: John Lacey (Ireland)
Assistant referees: Peter Fitzgibbon, Eddie Hagan-O'Connell (both Ireland)
Citing Commissioner: Eugene Ryan (Ireland)
TMO: Sean Flannery (Ireland)