Full report on Friday night's game at the RDS Arena in Dublin.
The Ospreys endured a night to forget in Dublin as the reigning champions inflicted a thumping defeat on their visitors, running in seven tries.
There was little indication of what was to come as the Ospreys enjoyed the best of the opening exchanges, the action played out exclusively in the Leinster half, and they perhaps should have opened the scoring after some great work to win possession at a Leinster scrum.
Quick hands saw space open up for Johnny Kotze, the centre stopped metres from the line. The Ospreys kept up the pressure, probing left and right, but were unable to breach the home defence, Leinster winning turnover ball under their own posts to clear.
Having survived that, Leinster did what Leinster do, and grabbed the first try of the match 13 minutes in on their first excursion upfield, and it was oh, so easy.
The defence parted for captain Scott Fardy on the Ospreys 22 and it was a simple finish for Conor O’Brien, taking the ball on his skipper’s shoulder and trotting under the posts, Ciaran Frawley with the extras.
Having weathered the early storm it was the boys in blue who took control and Frawley extended the Leinster lead on 25 minutes with a penalty, Ospreys offside.
Leinster were in control and they extended their lead just after the half hour mark, their lineout maul marching the Ospreys backwards for Scott Penny to ground the ball on his senior Leinster debut, Frawley slotting over the touchline conversion to make it 17-0.
The Ospreys thought they had their first try just a couple of minutes later, a well worked move from a scrum on the Leinster 22 seeing Sam Davies making good ground before releasing James Hook to go over. However, as Davies was lining up the conversion, referee Marius Mitrea referred it to the TMO and the try was ruled out for a block in midfield by Kotze.
It was to prove a key moment as Leinster made the most of the reprieve, the penalty allowing them to move back into the Ospreys 22 where, after the forwards had tried to bludgeon their way through it was scrum half Nick McCarthy who stretched over the line to score.
Frawley’s conversion was good and Leinster enjoyed a huge 24-0 lead as they went back down the tunnel, the exact same scoreline at the break as the last time the two teams met at the RDS, at the start of the 2016/17 season.
HALF-TIME: LEINSTER 24-0 OSPREYS
The try bonus point was wrapped up inside five minutes from the restart.
The Ospreys repelled the Leinster lineout drive on the right, play swung the width of the park and back again before eventually settling under the posts where the ref and TMO were able to spot that Fardy had scored under a heap of bodies, Frawley adding the simplest of conversions.
Leinster kept the scoreboard ticking over, try number five coming in the 57th minute, Ed Byrne going over from close range after the hosts had countered from deep, running kicked ball back at their visitors. Frawley was again on target with the conversion.
Max Deegan hared over to score Leinster’s sixth in the 64tth minute and another two-pointer from Frawley meant that the Irish side now led 45-0.
An incredible passage of play then saw the Ospreys somehow fail to score at one end, before Leinster almost scored at the other. Davies created space for Tom Williams who cruised through a gap in the defence. Opting to go alone instead of shipping it to his right he found himself isolated deep inside the Leinster 22, losing possession.
Leinster full-back, Max Deegan hacked up field, showing good footballing skills to take him right up to the Ospreys line, only for Keelan Giles to keep up with him and haul him down just short having tracked back the length of the field.
The hosts brought up the 50 when Bryan Byrne slid over seven minutes from the end, Frawley keeping his perfect record with the boot going as he clocked up 17 points.
Despite enduring a torrid evening the Ospreys did, eventually get on the scoreboard in the final minute, Davies teeing up Hanno Dirksen to score before adding the extras but the score did little to gloss over what was the Region’s heaviest ever defeat.