Rio Dyer celebrated his Wales call up with two tries to clinch a rousing victory for Dragons over Ospreys.
The 22-year-old wing crossed twice in the second-half, including a stunning solo run from half-way, to settle a thrilling Welsh derby at Rodney Parade.
Aaron Wainwright and Bradley Roberts also scored in a game that saw both sides reduced at times to 13 men.
Owen Watkin's Ospreys' try set up a nail-biting climax after earlier scores by George North and Scott Baldwin.
However despite losing Elliott Dee and Sean Lonsdale to yellow cards in a frantic final five minutes, Dragons held on for a win that will do the region the power of good.
It looked set to be a very different story when North stormed over from 30 metres out after less than 40 seconds.
That score meant Ospreys managing to silence the usually raucous atmosphere inside Rodney Parade at the off.
Jack Walsh took over at fly-half for Ospreys from injured Stephen Myler and could not have made a bigger early statement.
The Australian fly-half glided through the Dragons midfield before releasing North for a clear run.
Walsh converted and then traded penalties with JJ Hanrahan, just as Dewi Lake was trudging off.
The hooker was named in the Wales squad this week and tried to shrug off an early shoulder knock, only to concede defeat after just 17 minutes.
Scott Baldwin took his place and soon got on the scoresheet from a rolling line-out maul for the Ospreys' second try just moments after Wainwright hit back for Dragons.
The flanker was sent over by Harrison Keddie, making his 100th appearance, after a powerful burst by Jack Dixon.
Ospreys then imploded during a frenzied five minutes before half-time that saw them squander their 15-8 lead and reduced to 13 men.
Morgan Morris was shown a yellow card for tackling a player while offside as Dragons threatened.
Referee Adam Jones then sent Osprers lock Beard to join Morris in the sin bin and awarded a penalty try that Hanrahan converted to level 15-15 at half-time.
After Jack Dixon was held up, hooker Roberts peeled away from a line-out to crash over and Wainwright charged away before Dyer capped a wonderful week.
The 22-year-old showed just why he was named by Wales coach Wayne Pivac, standing up his opposite man before finishing with a stunning one-handed touch down for the bonus point.
With Dragons leading 27-15, Ospreys boss Toby Booth turned to the bench, throwing on Wales pair Justin Tipuric and Nicky Smith.
Walsh clawed back three points, but Ospreys had Owen Watkin to thank for saving a certain try after Dyer flew out of his own half before finding Wainwright in support.
That galvanised the visitors and with pressure came yet more cards.
But as Ospreys looked to put the 13 Dragons to the sword, Dyer picked off Nicky Smith's pass inside his own half and set off on a scorching run to the line.
Watkin crossed late on, but Dragons held out for the final 60 seconds for a thrilling victory,
Dragons: Sam Davies; Rio Dyer, Steff Hughes, Jack Dixon, Jared Rosser; JJ Hanrahan, Gonzalo Bertranou; Rhodri Jones, Bradley Roberts, Lloyd Fairbrother, Ben Carter, Will Rowlands (capt), Aaron Wainwright, Harrison Keddie, Ross Moriarty
Replacements: Elliot Dee, Aki Seiuli, Chris Coleman, Joe Davies, Sean Lonsdale, Rhodri Williams, Aneurin Owen, Max Clark
Ospreys: Max Nagy; George North, Owen Watkin, Michael Collins, Luke Morgan; Jack Walsh, Rhys Webb (capt); Gareth Thomas, Dewi Lake, Tomas Francis, Adam Beard, Alun Wyn Jones, Ethan Roots, Jac Morgan, Morgan Morris.
Replacements: Scott Baldwin, Nicky Smith, Tom Botha, Rhys Davies, Dan Lydiate, Justin Tipuric, Reuben Morgan Williams, Joe Hawkins
Referee: Adam Jones (WRU)
Assistant referees: Mike English & Wayne Davies (WRU)
TMO: Ian Davies (WRU)