Sexton converted five of his six penalty attempts to decide this scrappy Magners League encounter, bit it proved a night to forget for his opposite number Dan Biggar who left his kicking boots at the Liberty Stadium.
Biggar kicked an early penalty and converted the only try of the game, before failing with five penalty efforts – four of which were in the second half.
Justin Tipuric, captain for the night, claimed an opportunist 16th minute try as the Ospreys took a 10-9 lead into half-time after the flanker pounced and drove over from close range after ball had bounced off a team mate’s head.
But, in their 50th competitive at the Dublin venue, Leinster tidied up the mistakes and threatened with ball in hand – albeit with the Ospreys able to soak up the pressure.
The Ospreys’ hopes were helped prior to the game when James Hook was withdrawn due to a back spasm. Only four players were retained in the starting line-up from last weekend’s defeat at Cardiff.
Biggar and Sexton’s exchanged early penalites in driving rain before Sexton kicked Leinster into an 11th minute lead on a soggy pitch.
Eoin Reddan had his clearance kick blocked down near the Leinster line, the dropping ball bounced free from Ian Evans’ grasp and Tipuric nipped in to score under the posts.
Biggar tapped over the conversion but watched in horror when the ball moved on the tee just as he connected with what looked a straightforward penalty attempt on the half hour.
Sexton closed the gap to a single point after Duncan Jones was penalised before the fly half’s trusty boot guided his side home.
