Leinster moved to the summit of the United Rugby Championship table for the first time this season with an emphatic bonus triumph over Scarlets at the RDS tonight.

Jamie Osborne and Max Deegan helped themselves to a brace of tries and with four more players dotting down over the course of the proceedings, the eastern province enjoyed a comfortable evening at the office ahead of their meeting with Munster at the Aviva Stadium next weekend.

Scarlets found themselves on the back foot straight away in the Ballsbridge venue after their centre Johnny Williams was sin-binned inside the opening 30 seconds for a dangerous tackle on Garry Ringrose.

Leinster immediately punished the Welsh region as Sam Prendergast executed a neat one-two with Jamison Gibson-Park on his way to claiming a maiden try in professional club rugby on four minutes.

One of nine players from Ireland’s World Cup squad to make a seasonal return to the provincial scene, Gibson-Park proceeded to provide further assists for tries from Jimmy O’Brien Deegan – either side of Williams resuming his place in the Scarlets midfield.

Scarlets finally got up and running when the aforementioned Williams powered over on the right flank in the 27th minute, but with Prendergast having supplied conversions to those earlier five-pointers by O’Brien and Deegan, Leinster brought a 19-5 cushion into the interval.

After producing an excellent tackle to force the rampaging Kieran Hardy into touch on the resumption, Hugo Keenan broke superbly through the heart of the Scarlets’ rearguard to present Ringrose with a routine bonus point try on the stroke of 50 minutes.

Following Osborne’s first try on the hour mark, head coach Leo Cullen introduced U20s Grand Slam winner Fintan Gunne off the bench for his Leinster debut.

The former St Michael’s College scrum-half made a strong impression in the final quarter as he provided the final passes for tries from Jack Boyle and Osborne (his second).

Replacement fly-half Ross Byrne added a conversion to the latter score to bring him past 1,000 points in a Leinster jersey and there was just enough time left on the clock for Deegan to join Osborne in registering two tries for the rampant hosts.

Scorers for Leinster: Tries – J Osborne 2, M Deegan 2, S Prendergast, J O’Brien, G Ringrose, J Boyle. Cons – S Prendergast (3), R Byrne (4).

Scorers for Scarlets: Tries – J Williams.

LEINSTER: H Keenan; J Larmour, G Ringrose, J Osborne, J O’Brien; S Prendergast, J Gibson-Park; A Porter, R Kelleher, T Clarkson; J McCarthy, J Ryan; M Deegan, J van der Flier, C Doris.

Replacements: D Sheehan for Kelleher, T Furlong for Clarkson, R Byrne for Prendergast (all 51), J Boyle for Porter, R Molony for Ryan, F Gunne for Gibson-Park (all 61), C Frawley for Ringrose (67), S Penny for McCarthy (71).

SCARLETS: T Rogers; T Lewis, J Davies, J Williams, R Conbeer; C Titcombe, K Hardy; S Thomas, S Evans, H O’Connor; A Craig, J Price; B Williams, T Leatherbarrow, C Tuipulotu.

Replacements: W Jones for Thomas (46), M Jones for Craig (51), I Shenton for B Williams, I Nicholas for Rogers (both 57), R Elias for S Evans, S Williams for J Williams (both 61), S O’Connor for H O’Connor, A Hughes for Hardy (both 65).

Referee: H Davidson (SRU).