Leinster 43 Saracens 20
Leinster put Saracens to the sword with a ruthless second-half display at the RDS this afternoon to book their place in the Heineken Cup quarter-finals.
Saracens were only 22-12 adrift at half-time, turning around with the advantage of a blustery wind, but tries from Fergus McFadden, Isa Nacewa and Eoin O'Malley eased Leinster away.
In a free-flowing first half, man-of-the-match Sean O'Brien and Dominic Ryan (two) touched down for the hosts, with James Short and Kelly Brown crossing for Sarries.
But the Aviva Premiership high flyers were taught an attacking lesson after the break, and an injury-time try from Nils Mordt was meaningless in the end.
The bonus-point victory keeps Leinster five points clear of Clermont Auvergne and guarantees them top spot in Pool Two with a better head-to-head record over the French side.
With the wind at their backs, Leinster moved 12-0 ahead thanks to two early tries.
Brian O'Driscoll and Nacewa created an opening on the left, and the supporting Richardt Strauss put O'Brien over despite the presence of Brown.
There was a further injection of pace in the 12th minute when a wraparound move involving McFadden and Jonathan Sexton set up Shane Horgan for a run down the right.
Leinster secured quick ball and, from a position closer in, passes from O'Brien and Nacewa put 20-year-old flanker Ryan over for a converted try.
Saracens pounced on a Leinster error to run in a settling 24th-minute score. Luke Fitzgerald's sloppy pass near the halfway line was gathered on the bounce by Short, who had the pace to scamper away and touch down by the posts.
Owen Farrell added the conversion, and although Sexton pulled a penalty back after Rhys Gill dropped a scrum, there were more encouraging signs for Sarries.
Brad Barritt got his legs pumping on a huge surge into the Leinster 22, Carlos Nieto rumbled forward on the recycle and a subsequent knock on let Leinster off the hook.
But they could do nothing about the brilliant move which led to Brown's 33rd-minute effort.
Sarries gobbled up Fitzgerald's clearance kick before Schalk Brits roared forward linking with David Strettle, who offloaded for Andy Saull to send Brown over in the right corner.
Farrell failed with the conversion, and as the open style of rugby continued, Leinster mustered a response before the break.
O'Brien burst past two tacklers and, after a well-managed ruck, Sexton's long pass allowed Shane Jennings to lay off for Ryan to grab his second try.
Sexton tagged on the tricky conversion for a 10-point buffer at half-time, and it was his half-break that ignited Leinster's attack again for their bonus point try.
After soaking up some Sarries pressure, Sexton and O'Driscoll exposed the Sarries defence near halfway, Strauss then took the ball on and McFadden had a comfortable 30-metre run to the line, with Sexton adding the extras.
A Farrell penalty made it 29-15, but another sumptuous score saw Leinster put the result beyond doubt. Sexton, O'Driscoll and O'Brien were involved in a stylish break which finished with Nacewa stepping past Mordt for the try.
Three minutes later, Farrell's missed tackle invited replacement O'Malley through and he jinked his way past the covering Short for a classy seven-pointer.
A raft of substitutions broke up the tempo and after Leinster's Devin Toner saw yellow for collapsing a maul, Sarries salvaged some pride as Barritt put Mordt over for the ninth try of an entertaining European tie.