Jonathan Sexton kicked all of Leinster's points as they scraped their way to a 15-10 win over the Ospreys at the RDS on Friday.
Sexton converted five of his six penalty attempts to see off an understrength Ospreys side in a scrappy Magners League encounter, but it was a night to forget for his opposite number Dan Biggar.
Biggar kicked an early penalty and converted the only try of the game, before failing with five penalty efforts - four of which were in the second half.
Flanker Justin Tipuric, the region's second youngest ever captain, claimed an opportunist 16th minute try as the Ospreys took a 10-9 lead into half-time.
But, in their 50th competitive game at the Dublin venue, Leinster tidied up the mistakes and threatened with ball in hand - albeit with the Ospreys able to soak up the pressure.
Both sides made wholesale changes from their last outings, a flood of Ireland internationals returning on the back of Leinster's bonus point win over Connacht.
Tom Prydie was added to the Ospreys bench just before kick-off, replacing James Hook who was withdrawn due to a back spasm. Only four players were retained in the starting line-up from last weekend's defeat at Cardiff.
One of them, Biggar, punished an early maul infringement with his opening penalty, but a fine catch from Shane Horgan got Leinster moving and Sexton's opener soon followed.
Solid defending from the Ospreys stopped Devin Toner and Brian O'Driscoll short of the try-line, before Sexton kicked Leinster into an 11th minute lead on a soggy pitch.
It took a well-timed tackle from Luke Fitzgerald to thwart Rhys Webb after a nippy tap-and-go from the Ospreys scrum-half, but the visitors touched down from the very next phase.
Eoin Reddan had his clearance kick blocked down near the Leinster line, the dropping ball bounced free from Ian Evans' grasp and Tipuric nipped in to score under the posts.
Biggar tapped over the conversion but watched in horror when the ball moved on the tee just as he connected with what looked a straightforward penalty attempt on the half hour. His scuffed kick bounced off the underside of the crossbar and Leinster cleared.
Leinster had the better of the first half's final 10 minutes, with Reddan and Horgan sparking a counter-attack from deep. The Ospreys frustrated them at the breakdown, until Duncan Jones went offside and Sexton closed the gap to a single point.
Biggar's luck deserted him again when he struck the post from a 42-metre penalty as the second half got under way. But Sexton rewarded his forwards for a good bout of play, clipping over his fourth penalty success.
The two kickers miscued when presented with their next chances, and then Webb's throwing away of the ball before a Leinster lineout allowed Sexton make it 15-10.
Biggar failed with two more attempts - from long range and out wide on the right - and the Ospreys, despite a late rally, seemed content to take the bonus point.
Fitzgerald looked the most threatening of Leinster's runners, but spilled possession and slow ruck ball prevented Joe Schmidt's men from striking for a try.
Pens: Sexton 5
Leinster: 15 Luke Fitzgerald, 14 Shane Horgan, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Fergus McFadden, 10 Jonathan Sexton, 9 Eoin Reddan, 8 Jamie Heaslip, 7 Shane Jennings, 6 Dominic Ryan, 5 Devin Toner, 4 Leo Cullen (capt), 3 Mike Ross, 2 Richardt Strauss, 1 Cian Healy.
Replacements: 16 Jason Harris-Wright, 17 Heinke van der Merwe, 18 Clint Newland, 19 Nathan Hines, 20 Rhys Ruddock, 21 Isaac Boss, 22 Ian Madigan, 23 Eoin O'Malley/Isa Nacewa.
Ospreys: 15 Barry Davies, 14 Nikki Walker, 13 Sonny Parker, 12 Ashley Beck, 11 Richard Fussell, 10 Dan Biggar, 9 Rhys Webb, 8 Ryan Jones, 7 Justin Tipuric (capt), 6 Tom Smith, 5 Ian Evans, 4 Ian Gough, 3 Craig Mitchell, 2 Huw Bennett, 1 Duncan Jones.
Replacements: 16 Mefin Davies, 17 Ryan Bevington, 18 Cai Griffiths, 19 James Goode, 20 Jonathan Thomas, 21 Jamie Nutbrown, 22 Gareth Owen, 23 Tom Prydie .
Referee: Nigel Owens (WRU)
Assistant Referees: Simon McDowell, M Hermin (both IRFU)
TMO: Seamus Flannery (IRFU)