Rónan Kelleher opened his Leinster Rugby try account with a well-taken hat-trick in their 53-5 Guinness PRO14 win over Ospreys at the RDS.

The defending champions marked their first home game of the new season with an eight-try display, Fergus McFadden and 21-year-old hooker Kelleher crossing early on before Joe Tomane’s first home score for the province had them 22-0 ahead at half-time.

Back in Ireland just a week on from losing 38-14 to Ulster, the Ospreys’ only consolation in Dublin was a late effort from Luke Morgan. Kelleher, the man-of-the-match, completed his hat-trick by the 49th minute and replacements Max Deegan, Harry Byrne and Michael Milne finished off this runaway victory.

An early Lloyd Ashley offside was punished with an opening penalty from Ross Byrne who then created McFadden’s try. Rory O’Loughlin reacted quickest to a turnover, chipping over the top with Hugo Keenan first to the ball, and a penalty advantage developed before Byrne’s cross-field kick was grounded by McFadden in the right corner.

An inviting gap in the Ospreys midfield was ruthlessly exploited when Peter Dooley sent Will Connors galloping past halfway and he fed the supporting Kelleher who showed impressive pace to romp over from outside the 22 and increase the lead to 8-0.

Ospreys were foiled by Caelan Doris’ turnover penalty and a second lineout steal of the night from Scott Fardy. Their poor run of luck with injuries also continued as Dan Evans and Ashley both hobbled off, with new signing Ben Glynn making a brief PRO14 debut before injury struck.

Tomane soon thundered onto a Byrne pass and through a couple of attempted tackles to register Leinster’s third try, seven minutes before the interval. Following Byrne’s conversion, Ospreys enjoyed one of their best attacking spells but some late scrum pressure had no end-product.

The Welsh region began the second half with two hookers on the field – Scott Otten had to come on for replacement lock Glynn – and Kelleher in brilliant form. James Lowe chipped through and combined with Jamison Gibson-Park and Kelleher in a counter-ruck, the latter dribbling through and touching down from a few metres out.

With the bonus point secured, Leinster then used a penalty to set up a defence-splintering maul which handed Kelleher his third score. Another maul platform led to Deegan crashing over from a snappy Gibson-Park pass. Out-half Byrne landed both conversions to top off his 11-point contribution.

Dublin University scrum half Rowan Osborne came on to make his senior debut for Leinster, his speedy service a feature in the build-up to Byrne’s younger brother Harry slipping out of a tackle from Sam Cross to make it 46-0.

Academy prop Milne piled over at the end of twelve phases to crown his RDS debut with a converted try. Ospreys finally got off the mark eight minutes from the end, as reserve scrum half Matthew Aubrey’s break and quickly-taken lineout sent Morgan over.

Allen Clarke’s side lost replacement back rower Gareth Evans to the sin-bin for a no-arms challenge on McFadden, but avoided a ninth concession when Keenan’s late try was ruled out for a forward pass from Deegan.

Leinster Rugby return to the RDS Arena next Friday, 11 October, to face Edinburgh. Tickets are on sale now from €25.