Jonathan Sexton marked his seasonal debut with 16 points as Leinster won 31-19 at the RDS to end the Ospreys’ run at the top of the GUINNESS PRO12.,,

Sexton converted his own try on the stroke of half-time, adding to an earlier Josh van der Flier effort and a penalty try, to leave the in-form Welsh region 17 points adrift.

A second try from man-of-the-match van der Flier was cancelled out by Ben John, and the Ospreys gradually lifted their performance on a night that captain Alun Wyn Jones and Jeff Hassler made their 200th and 50th appearances respectively.

The visitors’ bonus point push gathered pace while Sexton was in the sin-bin as replacement Dafydd Howells (71 minutes) and James King (73) crossed in quick succession, but their late revival was not enough in the end.

Leinster have now moved temporarily up to third in the PRO12 table, with van der Flier, Cian Healy, Mick Kearney and Noel Reid among the players to shine during that stellar three-try first half.

Back for his first game since shoulder surgery in the summer, Sexton clipped over a close range fourth-minute penalty to reward a Garry Ringrose-inspired kick chase down the right touchline.

Scott Baldwin won the first of two ruck penalties that briefly broke up Leinster’s momentum in attack, but Reid’s clever kick got them into scoring range again and excellent flanker van der Flier clinically drove in under the posts in the 18th minute.

The Ospreys blew a gilt-edged maul opportunity after Isa Nacewa’s try-saving tackle on Hassler, before Dmitri Arhip’s high challenge on Nacewa in the 25th minute, on the back of repeated infringements, earned the Moldovan prop a yellow card.

Although Luke McGrath had a try in the left corner ruled out for a marginal knock-on from Sexton, the Leinster forwards maintained the pressure and back-to-back scrum penalties, five metres out, resulted in a penalty try for 17-0.

It got even better for Leo Cullen’s men when a breathless counter-attacking spell, sparked by Dave Kearney, eventually ended with Zane Kirchner sending Sexton over wide on the left.

The second half was only five minutes’ old when van der Flier took a great line off a Sexton pass to slip out of a tackle and then step away from Dan Biggar, with Sexton quickly converting the bonus point score.

Rhys Webb’s knock-on with the try-line in sight summed up a mostly frustrating evening for the Ospreys, ruining a terrific break from Josh Matavesi.

However, winger John’s fourth try of the campaign soon followed soon, the Ospreys finally getting some reward for their width – something that was so evident in their three previous bonus point victories.

As Leinster continued to leak penalties, an offside Sexton paid the price with ten minutes in the bin, and Biggar sent Howells raiding in from close range. Sam Davies’ break played in flanker King for their third touchdown, but they were held scoreless for the remainder.

LEINSTER SCORERS: J. van der Flier (2 tries), Penalty try, J. Sexton (1 try, 4 conversions and 1 penalty)

OSPREYS SCORERS: B. John (1 try), D. Howells (1 try), J. King (1 try), D. Biggar (2 conversions)

LEINSTER:

15. Zane Kirchner
14. Isa Nacewa CAPTAIN
13. Garry Ringrose
12. Noel Reid
11. Dave Kearney
10. Jonathan Sexton (Dan Leavy, 79)
9. Luke McGrath (Jamison Gibson Park, 60)
1. Cian Healy (Jack McGrath, 49)
2. Sean Cronin (James Tracy, 54)
3. Tadhg Furlong (Mike Ross, 64)
4. Devin Toner
5. Mick Kearney (Ross Molony, 54)
6. Jordi Murphy (Rhys Ruddock, 49)
7. Josh van der Flier (Joey Carbery, 71)
8. Jamie Heaslip

OSPREYS: Sam Davies; Jeff Hassler, Ashley Beck, Josh Matavesi, Ben John; Dan Biggar, Rhys Webb; Paul James, Scott Baldwin, Dmitri Arhip, Lloyd Ashley, Alun Wyn Jones CAPTAIN, James King, Justin Tipuric, Tyler Ardron.

REPLACEMENTS: Sam Parry, Nicky Smith, Ma’afu Fia, Bradley Davies, Dan Baker, Tom Habberfield, Dafydd Howells, Dan Evans.

REFEREE: Marius Mitrea (FIR); ASSISTANT REFEREES: Matteo Liperini (FIR), Stuart Gaffikin (IRFU); TELEVISION MATCH OFFICIAL: Carlo Damasco (FIR).