|Ospreys (6) 9|
|Pens: Biggar 2 Drop-goal: Biggar|
|Leinster (10) 22|
|Tries: D Kearney 2, Reid Cons: Sexton 2 Pen: Sexton|
Wing Dave Kearney crossed for two clinical tries as Leinster climbed to the top of the Pro12 table with their first win against Ospreys in Swansea since 2009.
The Ireland wing scored the opening and finishing tries against a much-changed home team.
Dan Biggar dropped an early Ospreys goal and added two penalties.
But Leinster underlined their dominance with a memorable Noel Reid try and the home side were unable to respond.
Six Nations undercurrent
Two fly-halves rated by many as the best 10s in the British Isles faced each other with the 2016 Six Nations looming - Ireland host Wales in their opener in Dublin on Sunday, 7 February.
Biggar and Johnny Sexton were more than familiar with each other beforehand and are among the leading contenders to don the British and Irish Lions' 10 jersey in New Zealand in 2017.
Sexton won the personal battle on this occasion, taking the man of the match award, including a textbook cross-kick for Kearney's opening try.
Leinster went to Swansea with six consecutive Pro12 wins while Ospreys' unbeaten run in the competition stood at five.
But defeat means the Welsh team stay seventh in the table after their poor start to the campaign.
Leinster's European Champions Cup campaign is over but the Welsh region remain in the hunt for a place in the quarter-finals, with a trip to Clermont Auvergne next up.
And that explained why Ospreys left Wales lock Alun Wyn Jones on the bench until the 55th minute among seven starting changes, while Leinster were at full strength to take over from Scarlets at the top of the table.
Future England open-side?
Ospreys' Wales open-side Justin Tipuric joined lock Jones in being rested, giving Rugby Football Union scouts Joe Lydon and Richard Hill the chance to watch 19-year-old Sam Underhill in action.
The United States-born, England-qualified flanker's impressive contribution included a thundering tackle that prompted Sexton to throw the ball forward near his own line.
Kearney's try was the key moment in the opening period and centre Ben Te'o's offload to release replacement Noel Reid as the game wore on left the home side with no choice but to chase the game.
However, Leinster's greater experience ensured there was to be no fightback, and their superiority was highlighted when wing Kearney burst through the middle of the home defence before sliding over for a fine try.
Ospreys: Dan Evans; Jeff Hassler, Jonathan Spratt, Owen Watkin, Hanno Dirksen; Dan Biggar, Brendon Leonard; Paul James (capt), Scott Baldwin, Aaron Jarvis, Lloyd Ashley, Rory Thornton, James King, Sam Underhill, Dan Baker.
Replacements: Scott Otten, Nicky Smith, Ma'afu Fia, Alun Wyn Jones, Justin Tipuric, Tom Habberfield, Sam Davies, Eli Walker.
Leinster: Rob Kearney; Isa Nacewa (capt), Ben Te'o, Luke Fitzgerald, Dave Kearney; Johnny Sexton, Luke McGrath; Jack McGrath, Richardt Strauss, Tadhg Furlong, Devin Toner, Mike McCarthy, Rhys Ruddock, Sean O'Brien, Jamie Heaslip.
Replacements: Sean Cronin, Peter Dooley, Marty Moore, Tom Denton, Dominic Ryan, Eoin Reddan,. Ian Madigan, Noel Reid.
Referee: David Wilkinson (IRFU)
Assistant Referees: Ben Whitehouse, Simon Rees (both WRU)
Citing Commissioner: Aurwel Morgan (WRU)
TMO: Jon Mason (WRU)