The four league points gained by Leinster at the Liberty Stadium took them level on points with second-placed Llanelli Scarlets, who travel to face Edinburgh.
Sixteen points from the boot of Felipe Contepomi and tries from Shane Horgan and Rob Kearney sealed the Irish side’s first Magners League away victory against the Ospreys.
The second-string Ospreys were missing a raft of players for today’s Wales versus South Africa Test yet they opened the scoring through the boot of Shaun Connor. But Leinster hit back, first through Contepomi’s penalty and then a try for Horgan after 18 minutes.
Kearney caught O’Driscoll’s up and under before the ball was released right and Contepomi provided a sublime try-scoring pass to Horgan, with the Pumas’ star converting from the touchline.
Connor then reduced the deficit to one point with his third penalty after the Leinster backs were caught offside before Leinster recorded their second try after a pass, possibly forward, from Contepomi to O’Driscoll was ignored by Scottish referee Andy MacPherson, with the Irish skipper providing the try-scoring pass to Kearney.
The Ospreys were relying on the boot of Connor, and a drop-goal on the stroke of half-time reduced the interval deficit to 17-12.
Prop Cian Healey stepped off the bench and almost made an immediate impression but had his try ruled out by the video referee, before flanker Keith Gleeson was sin-binned for lashing out at Andy Lloyd.
The Ospreys punished this indiscipline when teenage fullback Gareth Owen scored the hosts’ opening try, despite O’Drsicoll’s arm being under the ball, but Contepomi proved the difference once more, kicking a hat-trick of penalties to finally break Ospreys’ resistance.
