Aled Brew scored twice in the first half before Toby Faletau added a third as the Dragons clinched a bonus point. But 18 points from Treviso fly-half Kris Burton helped the Italians claim their first RaboDirect Pro12 win in Wales at Rodney Parade.
It looked set to be a different story when Brew stormed over for the opening try of the game following penalties by Lewis Robling and Kris Burton. Treviso hit back after Tonderai Chavhanga was stripped of the ball in a tackle before Burton and Robling exchanged further kicks.
Brew raced clear for his second after intercepting a pass in midfield but Italy full-back Luke McLean responded to leave the scores level 18-18 at half-time. The Dragons again started brightly with another try, a second in successive games for Wales star Faletau.
But again the home side failed to seize the initiative and Burton scored in the 55th minute. The fly-half missed the conversion but kicked a third penalty after Dragons flanker Lewis Evans was sin-binned to nudge Treviso ahead by a point.
Treviso prop Michele Riizzo followed Evans moments later but Jason Tovey missed the resulting penalty and then saw his pass picked off by Alberto Sgarbi for a bonus-point try seven minutes from time.
Burton crucially kicked the conversion to open an eight-point try but Treviso were reduced to 13 men for the final five minutes when replacement Fabio Semenzato was sin-binned.
Opposite number Hughes scorched through three minutes from time – to claim a bonus point – but the Dragons could find a match winner.
