The Dragons moved level on points with the fifth-placed Ospreys after a solid 28-20 win over their Welsh rivals at Rodney Parade on Saturday.
Paul Turner's side also moved a step closer to securing a Heineken Cup spot for next season in a pulsating Magners League encounter.
The Dragons thoroughly deserved their victory as they never allowed their much vaunted opponents to settle at any time in the match and hit them with three splendid tries.
First-half scores from Will Harries and Matthew Watkins helped the Dragons establish a 21-10 half-time advantage, with James Hook having crossed for the visitors.
Aled Brew stretched the hosts' lead in the second period with their third try before Andrew Bishop's late consolation.
The home side were first on the scoreboard when Jason Tovey kicked a 45-metre penalty after the Ospreys were penalised for diving over at a ruck.
Five minutes later the Dragons shocked the visitors with a try of rare quality. A clever pass from Wayne Evans sent Huw Gustafson away for the prop to storm 35 metres deep into the Ospreys 22. The ball was recycled and a neat kick from Tovey saw Harries win the touchdown in the corner.
Tovey missed the conversion but minutes later he kicked another penalty to leave the Ospreys 11 points down inside the first 10 minutes.
Dan Biggar opened the visitors' account after 13 minutes with a 30-metre penalty.
The game continued at a frenetic pace with the Dragons having the better of the play, harrying the Ospreys into errors at almost every opportunity.
The visitors were badly rattled by the ferocity of the Dragons' play. Tovey and Evans at half-back controlled matters for the hosts with some impressive tactics, Evans sniping around the scrum and ruck area and Tovey gaining large chunks of ground with some huge kicks.
Eventually the Ospreys got their game together and, after 27 minutes, following a period of sustained pressure, James Hook forced his way over in the corner and Biggar kicked a splendid touchline conversion.
Minutes later the Dragons were dealt a further blow when Dan Lydiate, their influential flanker, was helped from the field with a leg injury.
Five minutes before the interval Tovey kicked another penalty after the Ospreys were penalised for offside and, right on the stroke of half-time, the Dragons went further ahead courtesy of a magnificent solo try from Watkins.
The centre received the ball from a ruck 40 metres out and tore the Ospreys' defence apart before rounding the last defender for the score to give the Dragons a richly-deserved 21-10 interval advantage.
The Ospreys were first to score in the second half.
Lee Byrne did brilliantly to field his own up and under to put the Dragons under pressure and, when the home side were penalised, Biggar reduced the arrears with a simple penalty after 55 minutes.
But soon after the Dragons went further ahead when Brew broke away from a ruck 20 metres out and burst through the tackle of Marty Holah for a try under the posts which Tovey converted.
Biggar and Ian Evans were replaced by Sonny Parker and Ian Gough as the Ospreys sought to get back into the game and gain some composure to their play.
The Ospreys were beginning to dominate in terms of possession and territory but frequent errors by Mike Phillips, who had a nightmare of a match, prevented them from making much headway.
They did manage a late consolation from Bishop, which Hook converted from the touchline, but it was not enough to affect the result.
For the Dragons:
Tries: Harries, Watkins, Brew
Con: Tovey 2
Pen: Tovey 3
For the Ospreys:
Tries: Hook, Bishop
Con: Biggar, Hook
Pen: Biggar 2
Dragons: 15 Martyn Thomas, 14 Will Harries, 13 Matthew Watkins, 12 Ashley Smith, 11 Aled Brew, 10 Jason Tovey, 9 Wayne Evans, 8 Toby Faletau, 7 Gavin Thomas, 6 Danny Lydiate, 5 Luke Charteris, 4 Rob Sidoli, 3 Pat Palmer, 2 Tom Willis (capt), 1 Hugh Gustafson.
Replacements: 16 Steve Jones, 17 Ben Castle, 18 Andrew Coombs, 19 Hoani Macdonald, 20 Tom Riley, 21 James Arlidge, 22 James Leadbeater.
Ospreys: 15 Lee Byrne, 14 Tommy Bowe, 13 Andrew Bishop, 12 James Hook, 11 Nikki Walker, 10 Dan Biggar, 9 Mike Phillips, 8 Ryan Jones (capt), 7 Marty Holah, 6 Jerry Collins, 5 Ian Evans, 4 Jonathan Thomas, 3 Adam Jones, 2 Huw Bennett, 1 Paul James.
Replacements: 16 Richard Hibbard, 17 Ryan Bevington, 18 Ian Gough, 19 Filo Tiatia, 20 Jamie Nutbrown, 21 Sonny Parker, 22 Gareth Owen.
Referee: Nigel Owens (WRU)
Assistant Referees: Sean Brickell (WRU), David Jones (WRU)
TMO: Tony Rowlands (WRU)