Fielding a youthful side, Leinster lost their grip on pole position in the Magners League as the Newport Gwent Dragons ran in four first tries at Rodney Parade to secure an encouraging 30-14 win which has vaulted them back into the play-off zone.

The Dragons will take in Christmas as the best-placed Welsh region in the Magners League, with Sunday’s four-try dismissal of Leinster moving them up to fourth – a point ahead of the Ospreys.

Indeed, the top seven sides in the league are currently separated by just four points as the mouth-watering series of festive fixtures moves into view.

The bonus point was within the Dragons’ grasp by the 35th minute as Aled Brew, James Arlidge, Wayne Evans and Richard Fussell all helped themselves to tries, exploiting the gaps in a sluggish Leinster defence.

Heartened by what he saw, Dragons boss Paul Turner said the five-point return did not flatter his side.

"We would have taken a result like that before the game, we played some great stuff – in the first half, especially," he said.

"We tightened up a bit in the second half and Leinster threw a bit at us, but we were probably 30 points better than them on the day.

"There was a bit of experience out there for us. The pack laid the platform, there was a lot of control from James Arlidge, Wayne Evans is in the form of his life, Jason Tovey played well too.

"I know that Leinster had a lot missing but we still had to beat them, that laid down a marker."

The Leinster management rotated their squad, resting a whole host of Ireland internationals after their busy November campaign, and debutants Eoin O’Malley, Rhys Ruddock and Dominic Ryan were promoted to the province’s starting line-up.

The Dragons, who pipped Edinburgh 9-8 in their most recent game, welcomed back Wales forwards Danny Lydiate and Luke Charteris, with giant lock Charteris standing in as captain in the injury enforced absence of Tom Willis.

Dragons fly-half Arlidge missed an early penalty chance but just a minute later, a quick-witted move was finished off in the right corner by winger Brew. Flanker Gavin Thomas, centre Tom Riley and full-back Tovey were all involved in the build-up as Leinster were badly caught out.

5-0 down, the European champions missed an immediate opportunity to reply when Fergus McFadden was narrowly wide with a difficult penalty, but the Ireland ‘A’ centre redeemed himself with a successful 14th minute penalty.

The complexion of the game changed nine minutes later though, when Arlidge slipped through for an opportunist try. With flanker Ryan down receiving medical treatment, Leinster were left stunned when referee Simon McDowell allowed Arlidge tap a quick penalty and scoot in at the left corner from five metres out.

Leinster closed the gap to 10-6 when, after a bout of forward pressure which saw Ruddock and Stephen Keogh rumble on, young number 10 Ian McKinley slotted a terrific drop goal from a central position.

Again though, the Dragons’ ability to outfox the Leinster defence came to the fore before half-time as they made certain of the bonus point and gave the visitors a mountain to climb in the second half.

First, scrum half Evans speared his way through a gap and dotted down, with Arlidge adding his first conversion, and then some slick passing gave winger Fussell enough space to squeeze over in the left corner and Tovey tagged on a superb conversion from the touchline.

It could have been worse for Leinster but Riley knocked on when presented with a try-scoring chance on the half hour mark and O’Malley also reacted well to thwart a move under his own posts.

The Dragons’ physicality up front and very effective lineout gave them the platform to strike for the tries, and Leinster’s lacklustre defending was allowed the Welsh region to dictate in front of a typically vocal Rodney Parade crowd.

24-6 in arrears at half-time, Leinster needed to hit back quickly in the second half and a McFadden penalty got them up and running.

The Irish province were enjoying more territory, but a Tovey penalty brought them back down to earth and the Dragons handled anything the young Leinster backs threw at them.

Neither side covered themselves in glory as the game went through a lull during the third quarter, before Arlidge fired over another penalty to stretch the Dragons’ advantage to 30-9 and put a seal on the result.

McFadden threatened with ball in hand and McKinley tried to claw back territory for his side, and Leinster deservedly broke through for a late try when a string of passes from left to right teed up David Kearney for a short dart to the line.

The damage had been done in the first half and although Leinster salvaged some pride in an evenly-contested second period, the Dragons were well on top in most facets of play as they made it eight wins in-a-row in all competitions at Rodney Parade.

Speaking afterwards, Leinster coach Michael Cheika, whose charges are back on the European trail next week, said: "The first half performance was disappointing. We got caught on the hop and nothing went our way.

"It was always going to be tough with the amount of experience we were missing. We had to regroup at the break and I thought we did well in the second half."