The Dragons secured the fastest bonus-point try in the Magners League this season with a 30-14 win over the Ospreys which moves them up to fourth.
When television match official Neil Ballard confirmed that wing Richard Fussell had grounded the ball in the left corner, it meant the Dragons had pierced the European champions' defence four times in just 33 minutes.
And it could have been faster had centre Tom Riley held on to the ball with the line at his mercy when receiving a pass from Fussell on 29 minutes.
This was not the Leinster team which will be back in Wales on Saturday to play the Scarlets in Round Three of the Heineken Cup as coach Michael Cheika rotated his squad.
But that is not to undermine the superb effort from a Dragons side which has been revitalised this season and seem to have found their way in the league.
Their try-fest started as early as the fourth minute when flanker Gavin Thomas, centre Tom Riley and full-back Jason Tovey combined to send former Wales wing Aled Brew over in the right corner.
And, after centre Fergus McFadden had booted a Leinster penalty, Arlidge caught the Irish completely cold by taking a quick tap-penalty inside their 22 and diving over in the right corner for an opportunist score.
Outside-half Ian McKinley dropped a 35-metre goal but it only broke the Dragons' momentum briefly as a drive up the middle by the pack gave scrum-half Wayne Evans a great chance to sneak through a gap near the posts which he accepted gratefully.
Leinster were struggling to contain the home side and they broke for a fourth time when Fussell saw a chance and dashed to the corner.
A couple of penalties after the break from McFadden and Tovey kept the points difference at 19 and the Irish region slightly recovered some of the territory they gave away in the opening 40 minutes.
Their pack was good in the set-pieces but any attacks they tried to make were snuffed out by a resilient defence.
The game went through a quiet patch for 20 minutes as both coaches rang the changes before Leinster were accused of not binding at a scrum on their own 22 to give Arlidge an unmissable penalty in front of the posts.
Leinster maintained their defensive line but relied on McKinley's boot to take them out of their own half as the game wound down to the end.
Scrum-half Chris Keane also put in some good work for the Irishmen but there was little else for Cheika to be happy with
Finally, there was a consolation for Leinster as former Harlequins wing Simon Keogh was put away in the right corner for an unconverted try.
But it did little to dampen the home delight at a clincial win.
Tries: Brew, Arlidge, Evans, Fussell
Cons: Tovey 2
Pens: McFadden 2
Dragons: 15 Jason Tovey, 14 Aled Brew, 13 Rhodri Gomer Davies, 12 Tom Riley, 11 Richard Fussell, 10 James Arlidge, 9 Wayne Evans, 8 Grant Webb, 7 Gavin Thomas, 6 Dan Lydiate, 5 Luke Charteris (c), 4 Rob Sidoli, 3 Pat Palmer, 2 Steve Jones, 1 Hugh Gustafson.
Replacements: 16 Duane Goodfield, 17 Peter Bracken, 18 Hoani MacDonald, 19 Adam Jones, 20 Martyn Thomas, 21 Will Harries, 22 Alex Walker.
Leinster: 15 Niall Morris, 14 David Kearney, 13 Eoin O'Malley, 12 Fergus McFadden, 11 Simon Keogh, 10 Ian McKinley, 9 Chris Keane, 8 Stephen Keogh, 7 Dominic Ryan, 6 Rhys Ruddock, 5 Malcolm O'Kelly, 4 Devin Toner, 3 CJ van der Linde, 2 Bernard Jackman (c), 1 Ronan McCormack.
Replacements: 16 Richardt Strauss, 17 Mike Ross, 18 Trevor Hogan, 19 Paul Ryan, 20 Paul O'Donohoe, 21 Ian Madigan, 22 Michael Keating.
Referee: Simon McDowell (Ireland)