Leinster too good for Munster
The men in blue looked composed throughout and had the first score of the afternoon with O’Loughlin pirouetting through tackles to go in under the posts.
Ian Keatley got the Munstermen back in it with his breakaway try but O’Loughlin crossed again to restore the lead before half-time.
Keith Earls responded after the break with another score against the run of play, and despite his second try right at the death Leinster held on for a hard-fought victory.
Munster thought they’d opened the scoring after just 13 minutes but a long pass wide to Keith Earls was adjudged to have gone forward.
There was no doubt about O’Loughlin’s effort in the 17th minute as the outside centre danced and spun his way through the 22 to touchdown under the posts.
Munster’s Niall Scannell saw yellow for a deliberate knock-on but his teammates levelled things up in the sin-bin period with Keatley seizing on a loose pass to race away to the line.
Leinster though were determined to dictate the pace of the game and attacked relentlessly, with two crossfield bombs from Sexton gaining crucial ground.
Gaps appeared and O’Loughlin got his second on 35 minutes, with a trademark Sexton loop finding Joey Carbery who passed on to give the centre an easy run in.
The Dublin-based province led 14-7 at the break and immediately set about extending that lead in the second-half, with Barry Daly and Sexton both making inroads down the left.
The Aviva Stadium crowd were treated to a historic moment soon after, with Sexton adding a penalty and in the process becoming Leinster’s all-time leading points scorer, with rapturous applause ringing out around the ground.
But the joy was short-lived as a loose lineout gave Tommy O’Donnell the opportunity to streak 50 metres up the pitch and offload to Earls, who touched down in the corner despite Adam Byrne’s impressive covering tackle.
Ireland flyhalf Sexton was in typically metronomic form though and added two further penalties to surge his team into a 23-12 lead.
With ten minutes left to play Jamison Gibson-Park prodded the ball into the corner and with Barry Daly steaming in JJ Hanrahan got back in the nick of time to carry the ball into touch.
Munster staged one last attempt to steal the win and Earls went over in the corner with two minutes left to play, but following the missed conversion Rassie Erasmus’ men were content with a losing bonus-point.
Tries: O'Loughlin 2
Cons: Sexton 2
Pens: Sexton 3
Tries:Keatley, Earls 2
Leinster: 15 Joey Carbery, 14 Adam Byrne, 13 Rory O’Loughlin, 12 Robbie Henshaw, 11 Barry Daly, 10 Johnny Sexton (captain), 9 Luke McGrath, 8 Jack Conan, 7 Josh van der Flier, 6 Rhys Ruddock, 5 Scott Fardy, 4 Devin Toner, 3 Tadhg Furlong, 2 James Tracy, 1 Jack McGrath
Replacements: 16 Seán Cronin, 17 Cian Healy, 18 Michael Bent, 19 Ross Molony, 20 Jordi Murphy, 21 Jamison Gibson-Park, 22 Ross Byrne, 23 Fergus McFadden
Munster: 15 JJ Hanrahan, 14 Andrew Conway, 13 Chris Farrell, 12 Tyler Bleyendaal, 11 Keith Earls, 10 Ian Keatley, 9 Conor Murray, 8 CJ Stander, 7 Tommy O’Donnell, 6 Peter O’Mahony, 5 Billy Holland, 4 Robin Copeland, 3 John Ryan, 2 Niall Scannell, 1 Dave Kilcoyne
Replacements: 16 Rhys Marshall, 17 Liam O’Connor, 18 Stephen Archer, 19 Mark Flanagan, 20 Jack O’Donoghue, 21 Duncan Williams, 22 Rory Scannell, 23 Alex Wootton
Referee: Ben Whitehouse (Wales)
Assistant referees: Craig Evans (Wales), Wayne Davies (Wales)
TMO: Jon Mason (Wales)