While Leinster head coach Leo Cullen had initially selected 10 starters from last weekend’s tense Champions Cup semi-final triumph over Northampton Saints, this number increased to 11 when Josh van der Flier was drafted into the back-row to replace Will Connors shortly before kick-off.

Ronan Kelleher and Jimmy O’Brien were promoted to the first 15 following their appearances off the bench in Croke Park seven days earlier and they combined to good effect before the latter raced home from 70 metres out for Leinster’s third-minute breakthrough try.

This was the perfect start for the Blues on a warm night in the capital and their lead was subsequently enhanced when Ross Molony capitalised on excellent approach work from Caelan Doris to power over for his first Leinster try since January 2022.

Ross Byrne added his second bonus strike of the evening to move Leinster 14 points clear, but this advantage was sensationally wiped out by the visitors before the opening quarter had fully elapsed. Outside centre Owen Watkin got Ospreys up and running with a converted try on 14 minutes and the rejuvenated Welsh region followed up with an equalising score moments later.

An audacious crossfield kick from fly-half Dan Edwards landed into the arms of Luke Morgan on the right-wing and after consulting his TMO Andrew McMenemy, referee Sam Grove-White adjudged that Ciaran Frawley had tackled his opponents in the air beyond the Leinster line.

A penalty try and a yellow card for Frawley arose from this incident, but in the absence of the Irish international, Leinster regained momentum. When Ospreys full-back failed to control a grubber kick by Byrne on 27 minutes, Larmour supplied the finishing touches for a try that propelled the Blues towards a 21-14 interval buffer.

While the tie itself was still delicately poised, the hosts were nevertheless within sight of a bonus point upon the resumption. This is perhaps what fuelled Leinster’s explosive start to the second half, which was less than a minute old when they bagged their fourth try of the proceedings.

It is anticipated Jason Jenkins will have a big part to play in the business end of the season and the South African lock burst over the Ospreys line after Jimmy O’Brien had once again made significant metres in attack.

Cullen gradually started to alter his line-up as the third-quarter progressed, but it was a brace of starters who shone brightest for Leinster’s fifth try in the 54th-minute. Robbie Henshaw picked out Larmour on the right-flank after finding space deep inside into the Ospreys half and though he had a lot of work to do, the elusive winger showed a clean pair of heels to the opposition defence before doubling his tally for the game.

Even though this effectively placed the final outcome beyond doubt, Leinster were in mood to drop their performance levels during the closing-quarter of a game that was played in front of 15,750 spectators.

Supplementing Larmour’s hat-trick score on 77 minutes, Jamie Osborne, Charlie Nagatai and Tommy O’Brien also crossed over to round off a comprehensive victory for Leinster.

Scorers for Leinster: Tries – J Larmour 3, J O’Brien, R Molony, J Jenkins, J Osborne, C Ngatai, T O’Brien. Cons – R Byrne 5, C Frawley 3.

Scorers for Ospreys: Tries – O Watkin, Pen Try. Cons – D Edwards.

LEINSTER: C Frawley; J Larmour, J Osborne, R Henshaw, J O’Brien; R Byrne, L McGrath; A Porter, R Kelleher, T Furlong; R Molony, J Jenkins; R Baird, J van der Flier, C Doris.

Replacements: D Sheehan for Kelleher, J Conan for Molony, J Gibson-Park for McGrath (all 52), M Milne for Porter, T Clarkson for Furlong (both 56), C Ngatai for Byrne, T O’Brien for Henshaw (both 58), S Penny for Doris (71).

OSPREYS: M Nagy; L Morgan, O Watkin, K Williams, K Giles; D Edwards, R Morgan-Williams; N Smith, D Lake, R Henry; J Ratti, H Sutton; H Deaves, J Tipuric, M Morris.

Replacements: G Thomas for Smith, T Botha for Henry (both 52), J Morgan for Deaves, S Parry for Lake, J Walsh for Edwards (all 57), V Sekekete for Sutton, E Boshoff for Williams (both 71).

Referee: S Grove-White (SRU).