Reid and Dundon get Leinster off the hook
Dragons 19 Leinster 23
Two second-half tries rescued Leinster as they narrowly overcame a tough Dragons side.
Scores from hooker Aaron Dundon and centre Noel Reid glossed over a largely disappointing performance from the visitors, who looked nothing like the side who had won three games in a row in the Pro12 and Heineken Cup until a late fightback.
Matt O'Connor's side were without Ireland internationals like Brian O'Driscoll, Cian Healy and Jamie Heaslip and their absence showed in a poor first half.
Jimmy Gopperth's penalty did give Leinster the lead on 12 minutes but it didn't last long as Tom Prydie drew the hosts level with a long-range penalty shortly afterwards.
Leinster thought they had the game's opening try on 27 minutes when they capitalised on Jason Tovey's error under the high ball. Luke Fitzgerald moved the ball wide to Zane Kirchner and his chip kick was superbly collected and offloaded by Reid to put Gopperth in the corner.
After much deliberation by TMO Gareth Simmons he decided that Reid's foot had gone into touch when tackled by Prydie and the try was disallowed.
Four minutes later the Dragons scored a superb try of their own from a move starting inside their own half.
Leinster scrum half John Cooney was penalised for holding on after being put under pressure by opposite number Richie Rees at a scrum.
Rees took a quick penalty from five metres inside the Dragons' half and great juggling work by Patrick Leach set Prydie free out wide. He found centre Ross Wardle in support to go over in the corner and Tovey added the extras.
Prydie missed the chance to put the Dragons 10 points in front on 36 minutes and Gopperth brought Leinster back to within four with a penalty on the stroke of half-time.
But it was the Dragons who came out fighting after the break and they quickly extended their lead with a Tovey penalty.
Leinster were guilty of wasting a number of good opportunities in attack and had to make do with another Gopperth penalty for their points on 50 minutes.
Only when Dragons lock Adam Jones was sent to the sin bin on 57 minutes did the game swing dramatically in Leinster's favour. With a one-man advantage they kicked to touch rather than take the three points and soon pressed home their advantage as hooker Aaron Dundon powered over.
Leinster showed their class four minutes later with a second try, this time working the ball on the blind side for Kirchner to put Reid into space for a simple score.
But Leinster did not have it all their own way in the final 10 minutes and a yellow card for substitute Jack O'Connell either side of two Tovey penalties set up a grandstand finish.
A late attack left the Dragons five metres from the Leinster line but the visitors held on for the win.
Dragons – H Amos; T Prydie, P Leach, R Wardle, A Hughes (D Evans 54); J Tovey, R Rees (J Evans 54); O Evans (N Williams 54), S Parry, D Way (N Chaparro 71); A Jones, M Screech; J Groves, L Evans (c), N Talei.
Leinster – Z Kirchner; D Fanning (B Macken 71), L Fitzgerald, N Reid, L Tuqiri; J Gopperth, J Cooney; M Bent (J O'Connell 63), A Dundon (J Tracey 73), M Moore (T Furlong 71); Q Roux, T Denton (B Marshall); D Ryan (L Auva'a 63), S Jennings (c), R Ruddock.
REF – P Fitzgibbon (IRFU)