LEINSTER completed a comfortable double at Cardiff Arms Park to see off Cardiff Blues and consolidate their position in the RaboDirect Pro12 play-off places.
The Blues had been enjoying something of a revival at home, with three successive wins in three different competitions, but were outmuscled up front and out-thought at the back in a disastrous first half meaning even a gallant fightback after the break was never going to be enough.
Although both sides were depleted by international calls, they showed plenty of enthusiasm in a lively opening before Leinster took the lead with a straightforward Ian Madigan penalty.
The Blues were the first to threaten the try line, fly-half Rhys Patchell looping around centre Dafydd Hewitt before firing a long pass to Owen Williams. The winger took it at pace and kicked ahead, only for the ball to bounce too high for him to gather.
Patchell, again released by Wales Under-20s, equalised with a 40-yard penalty, but was off target with a similarly long-range effort, before Leinster lock Tom Denton was sent to the sin bin following an off-the-ball incident.
Leinster were still a man short when Madigan put them back in front with a penalty that struck a post and the bar before dribbling over. The fly-half added another three points - taking his season's tally to 100 - when the Blues infringed as they tried to recover from a goal-line fumble by Jason Tovey.
The European champions emphasised their superiority with a try by scrum-half Isaac Boss, who squeezed over from a ruck leaving Madigan an easy conversion.
Irish referee Peter Fitzgibbon angered the crowd when he ruled that Blues wing Harry Robinson had taken the ball back over his line before touching down and their mood was not improved when the Leinster pack drove at the resultant five-metre scrum and number eight Jordi Murphy dived over. Madigan gave his team a 20-point interval lead.
Patchell was short with a penalty to open the second period, but a gallop by number eight Robin Copeland took the Blues into the opposition 22 where Leinster's blitz defence kept the home backs at bay.
The Blues would not be denied, however, and a good handling move saw Tovey sneak in at the corner. Patchell's conversion attempt never left the ground, the kicker staring ruefully at the Arms Park mud.
Williams burst past two tacklers on the right touchline, but the Blues had to settle for a Patchell penalty for offside.
Patchell raised Blues hopes when he danced through to the line, but referee Fitzgibbon called play back for an earlier infringement.
The disappointment was heightened when Madigan stroked over a penalty on a rare Irish visit to home territory, although he was wide with an attempted drop goal.
Leinster re-established control as the game petered out with then usual flood of replacements, but never seriously threatened to claim a bonus point.