The Dragons dealt a blow to Leinster's title hopes with a convincing Celtic League win at Newport's Rodney Parade.
Dragons (23) 31
Tries: Wyatt, Forster (2)
Cons: Warlow (2)
Pens: Warlow (4)
Leinster (11) 18
Tries: Lewis (2)
Pens: Contepomi (2)
Gareth Wyatt and Kieran Lewis exchanged early tries, but fly-half Craig Warlow outdid opposite number Felipe Contepomi by kicking 16 points against eight.
Two Jason Forster tries either side of half-time sealed the win as the Dragons pack took a firm grip of the game.
But as they went chasing the fourth bonus-point score Lewis broke away from deep in his half for a fine second try.
Contepomi opened the scoring with a penalty, but the Dragons hit straight back through Wyatt.
The ex-Wales wing - just back from a dislocated shoulder and celebrating signing a new contract at Rodney Parade - put up a high kick.
Ireland and Lions international Denis Hickie fumbled, Gareth Baber hacked on, and Wyatt had the pace to outstrip the defence for the opening try.
Warlow and Wyatt combined for another fine attack, but had to be content with a penalty when full-back Aled Thomas failed to capitalise on an overlap.
High-flying Leinster hit back with quick ball from a 15m scrum, Hickie's long pass finding Lewis out wide where the centre was able to squeeze in past Wyatt's challenge.
Warlow hit his second penalty, but a kickable 34th-minute effort was booted to touch.
The Dragons won the line-out and set up a short-range driving maul from which captain Forster forced his way over.
Another attack by the home side on the stroke of half-time was held up over the line, but Warlow kicked the resultant penalty to make it 23-11 at the break.
It stayed that way for 24 minutes when Baber made an excellent sniping break and fed the supporting Rhys Thomas.
The prop went close, but it was Forster who was able to seize on the ball and cross for his second close-range effort.
It was all the Dragons as they went seeking a bonus point, but when another attack broke down in midfield John Hepworth pounced on the loose ball.
He fed centre partner Lewis, who had the pace and power to go the length of the field for his second try.
Warlow put to bed any slim hopes of a comeback with an 80th-minute penalty, but caused consternation to the home fans by limping off injured deep into injury time.
Dragons captain and man-of-the-match Jason Forster:
"We've been threatening to do that with our performances for some time, but it's nice to actually get the result.
"We've had a lot of injuries, but that's one of those things you just have to get on with.
"I'm pleased for everyone at this club that we got the win."
Dragons: A. Thomas, Wyatt, Brew, Bryant, Breeze, Warlow, Baber, Black, S. Jones, R. Thomas, Forster, Sidoli, Ringer, Hall, Oakley.
Replacements: Tuipulotu for Warlow (80), Maddocks for Black (61), Griffiths for Hall (61). Not Used: Brown, Anthony, Van Rensberg, Hinton.
Leinster: Dempsey, Kearney, Lewis, Hepworth, Hickie, Contepomi, Easterby, Corrigan, D. Blaney, Green, Byrne, Williams, Miller, Gleeson, Gissing.
Replacements: McCormack for Corrigan (75), Grissing for Byrne (61). Not Used: B. Blaney, Ronan, O'Riordan, Hickey, Brown.
Referee: Peter Allan (Scotland)