Leinster’s second half haul of 13 points – a Gordon D’Arcy try and eight points from the right boot of Felipe Contepomi – saw the defending Magners League champions secure temporary control of the table as they overcame the challenge of a youthful Ospreys side.

Leinster wrestled their way to the top of the standings above the Ospreys and long-time leaders Munster as they made it six victories on the trot in the Magners League.

But Leinster’s grip on top spot was only temporary as Munster gained a 20-9 win at the Dragons on Saturday to climb back to the summit.

The Ospreys, who were without 16 international due to Six Nations duty or injury, went 5-0 ahead thanks to a Sonny Parker try.

But Sean Holley’s side conceded some crucial second half scores as they slipped to only their second home defeat of the season.

Some late pressure yielded a drop goal from Dan Biggar which handed the hosts a losing bonus point, leaving them just three points behind their Irish conquerors in the table.

The first half was a tight affair as the Ospreys opened well against the more experienced visitors.

Biggar had the first shot at the posts but he pushed his eighth-minute penalty effort wide from 45 metres out.

The wet conditions made for difficult handling and neither side could get a territorial grip, with poor kicking from both sides of the pitch.

In only his second league game, Leinster scrum half Paul O’Donohoe enjoyed a good duel with his opposite number Jamie Nutbrown.

But neither player could exert much of an influence as errors continued to blight the opening period.

Leinster did go close to breaking the try deadlock when their Wallaby back rower Rocky Elsom lunged towards the whitewash, only to be denied by a well-positioned Cai Griffiths.

The Ospreys prop got his body under the ball as Elsom tried to score close to the posts, after Leinster’s stand-in captain Shane Jennings had launched a kick chase.

Defences were certainly on top at this stage but the home side managed to get on the scoreboard just on the stroke of half-time when centre Parker barged his way over.

Leinster were left kicking themselves when they allowed the former Welsh international to break past three tacklers and score a try which television match official Nigel Whitehouse confirmed.

Stan Wright and Cameron Jowitt were particularly guilty for allowing Parker muscle his way through. Biggar missed the conversion, leaving the Ospreys to take a 5-0 buffer into the second half.

Leinster had lost Isa Nacewa to a knee injury midway through the first half but another of their foreign imports, the league’s current top scorer Felipe Contepomi, increased his influence on the restart.

Contepomi kicked penalties after 42 and 52 minutes to nudge Michael Cheika’s men into the lead. His second penalty success came after Ospreys number 8 Filo Tiatia was sin-binned for killing the ball close to his own try-line.

With replacements Chris Whitaker and Sean O’Brien impressing on their introduction, Leinster assumed more control and they soon made their numerical advantage count.

On 56 minutes, Contepomi thundered up into the Ospreys 22 and offloaded for a sidestepping Gordon D’Arcy to power his way over past Andrew Bishop and Parker and score to the left of the posts.

Contepomi added the conversion for a 13-5 scoreline but the Argentinian was yellow carded, nine minutes later, when he was penalised for coming in at the side of a ruck as the Ospreys look to spread quick ball.

Tiatia’s return sparked the Ospreys back to life and they finished the game on the attack.

With an eight-point lead, Leinster seemed content to soak up the pressure and see out the win with man-of-the-match D’Arcy impressive in defence.

The Ospreys’ hopes really rested on gaining a late, losing bonus point and they looked to have missed out on their best opportunity in the dying minutes.

They moved the ball out to the left wing where they were just a pass away from scoring their second try. However, Jonny Vaughton’s pass to the lurking Tiatia did not go to hand and Leinster survived.

Survived, that is, until just a couple of minutes later when Biggar elected to take a drop goal as the Ospreys pressed in front of the Leinster posts.

Leinster, though, deserved the win on foot of their efforts in the early stages of the second half.

Speaking after the province’s fourth successive victory over the Ospreys, head coach Cheika said: "We played better at the start of the second half, with a bit more shape and better continuity, and we dominated territory from there.

"We knew that we weren’t playing very well in the first half. I didn’t have to say anything to the guys at half-time because there’s a real commitment in the squad to retain our title.

"We knew that these two games in Wales (away to the Scarlets and Ospreys) would be pivotal, and to win in Wales is no easy feat."