Leinster 37 Ospreys 19: Job done. On a highly satisfying night for Leinster, they copperfastened a semi-final back at the RDS next Saturday against Glasgow, with the prize a final at the same venue with either themselves or Ulster as the 'home' side. In the process, they laid their Ospreys bogey.

In rotating their squad with seven changes and securing that home semi-final, Leinster have also set themselves up nicely for a run-in which, with an Amlin Challenge Cup final to come a fortnight hence, means they could play another three knockout matches at home and with two trophies at stake.

Not the least satisfying aspect of the night was the manner a second-string frontrow knuckled down to work, and with plenty of oomph coming from Leo Cullen and Quinn Roux in the secondrow, the Leinster scrum had enjoyed an edge even before the changes. There is some irony in Jamie Hagan playing the best rugby of his career since his move to London Irish was confirmed, and furthermore the Munster-bound Andrew Conway scored a hat-trick on the most productive night of his four seasons with Leinster.

With Luke McGrath having a productive full debut and Jonny Sexton pulling the strings, as well as landing five from five, Leinster had particularly joy in moving the ball wide and then kicking over the Ospreys defensive line in what appeared to be a well-rehearsed ploy.

As is their wont, the Ospreys pushed up hard in defence and were ultra competitive at the breakdown, either obliging McGrath to do a fair amount of scavenging or spoiling Leinster possession. Nonetheless, their defence was pierced early on by a typically well executed Sexton wraparound before Leinster struck first in the seventh minute with a try that embodied all the slick interplay and skills set which runs through their ranks.

Moving turnover ball from right to left across their 22, as is his wont Seán Cronin injected some tempo to carry toward half-way, Isa Nacewa stepping in to scrumhalf and Kevin McLaughlin trucking it up before Sexton passed behind runners for Fergus McFadden to put through a wicked grubber which nutmegged Ross Jones for Andrew Conway to score.

Leinster were having joy putting the ball in behind the Ospreys, and after Conway had forced another attacking lineout with a kick and chase, he promptly doubled his tally for the season in this game. From Cullen’s feed off the tail, Luke McGrath sniped through a soft tackle and offloaded superbly for Conway to score.

However their intensity dropped off. First Dan Biggar tapped a penalty to himself and beat a poor tackle by Roux to be driven over the line by Sam Lewis and Jonathan Spratt, and added the conversion.

Joe Schmidt would have been equally displeased with the way some of his team switched off from a partially blocked kick by Conway to allow one-time Leinster Academy product Ross Jones to counter through a statuesque defence, before good hands by the halves, Lewis and Joe Bearman enabled Ben John to score.

The half ended with the arrival of the rain and a Sexton penalty, and with 65 seconds of the restart Conway completed his hat-trick. Again Leinster ran back an Ospreys kick from deep and though there didn’t seem much on again Con way located space in behind to chip Ross Jones and outsprint the ex-Leinster winger to kick on and score.

Sexton added a stunning touchline conversion and pushed Leinster more than two scores clear to reward a big scrum by his pack with a towering penalty, which was no bad idea against their bogey side. Sure enough, they weren’t inclined to go away and a prolonged siege ended with Tom Isaacs sliding in off Biggar’s long pass.

Biggar converted, but Sexton responded with another well-struck 40 metre penalty before playing a telling hand in their bonus point try. From a Seán O’Brien turnover, again Sexton chipped over the Ospreys defence wide out into space and under pressure from Conway, Isaacs deflected the ball inside where Cian Healy pounced and finished from 30 metres out like a winger.

Ian Madigan’s conversion extended his hot streak in this competition to 21 place kicks in a row. There were no injuries to report; O’Brien’s departure before the end merely due to cramp.