Leinster moved top of the PRO12 standings after impressing in a 22-9 victory over title rivals the Ospreys at Liberty Stadium on Friday.
Dan Biggar's drop-goal gave the Welsh region the lead, but the Irish province were the better side in the first-half and went into the interval 10-6 in front via Dave Kearney's try and Johnny Sexton's three-pointer.
Steve Tandy's team improved after the break and Biggar kicked his second penalty to bring them to within one point, but the visitors were clinical and further scores from Noel Reid and Kearney secured the win.
Even though Leo Cullen's men have struggled in Europe this season, their league performances have improved significantly as the year has gone on.
However, they suffered an early blow as inspirational number eight Jamie Heaslip was taken off injured.
Following that setback Biggar kicked a drop-goal to take the hosts in front, but the visitors regained their composure and went ahead through Kearney. The cross-field kick had already stretched the Ospreys' defence once in the game and the trick worked again as Sexton's inch-perfect effort was caught and well finished by the winger.
Biggar reduced the deficit from the tee before Leinster's four-point buffer was restored by the break via the boot of Sexton.
Cullen's outfit struggled in the early part of the second-half as they failed to control territory which allowed Tandy's team to build pressure, but a third penalty was the Welsh region's only reward.
That profligacy proved costly with the Irish province striking with their first significant attack of the half. It was another superbly constructed move, reminiscent of the Leinster of old, and was finished by replacement Reid, who had too much pace for the cover defence.
The Ospreys' defence then parted for the third time and allowed Kearney to rubber-stamp a fine victory.
Pen: Biggar 2
Tries: D Kearney 2, Reid
Con: Sexton 2
Ospreys: 15 Dan Evans, 14 Jeff Hassler, 13 Jonathan Spratt, 12 Owen Watkin, 11 Hanno Dirksen, 10 Dan Biggar, 9 Brendon Leonard, 8 Dan Baker, 7 Sam Underhill 6 James King, 5 Rory Thornton, 4 Lloyd Ashley, 3 Aaron Jarvis, 2 Scott Baldwin, 1 Paul James.
Replacements: 16 Scott Otten, 17 Nicky Smith, 18 Ma'afu Fia, 19 Alun Wyn Jones, 20 Justin Tipuric, 21 Tom Habberfield, 22 Sam Davies, 23 Eli Walker.
Leinster: 15 Rob Kearney, 14 Isa Nacewa (c), 13 Ben Te'o, 12 Luke Fitzgerald, 11 Dave Kearney, 10 Johnny Sexton, 9 Luke McGrath, 8 Jamie Heaslip, 7 Sean O'Brien, 6 Rhys Ruddock, 5 Mike McCarthy, 4 Devin Toner, 3 Tadhg Furlong, 2 Richardt Strauss, 1 Jack McGrath.
Replacements: 16 Sean Cronin, 17 Peter Dooley, 18 Marty Moore, 19 Tom Denton, 20 Dominic Ryan, 21 Eoin Reddan, 22 Ian Madigan, 23 Noel Reid.
Referee: David Wilkinson (Ireland)
Assistant Referees: Ben Whitehouse (Wales), Simon Rees (Wales)
TMO: Jonathan Mason (Wales)