Wing Dafydd Howells made the perfect start on his league debut as he intercepted a floated pass and raced over unopposed after 66 seconds.
Benetton hit back with lock Alessandro Zanni touching down before Tommaso Allan gave the Italians the lead at the break with two penalties.
Gavin Henson cut the lead to a point at the start of the second half before Braam Steyn struck for Benetton.
Zanni’s second of the night sent the Italians clear before Rhodri Williams darted over late on to snatch a losing bonus point.
Dragons, roared on by a passionate home crowd, made a dream start as Howells raced out the line, intercepted a pass and tore over after less than two minutes.
The Italians struck back, though, within minutes with a driving lineout five-metres out that was shunted over with lock Zanni the man to touchdown.
The home side were looking to impose their physicality from the start with Richard Hibbard and Brandon Nansen unloading big hits in the opening ten minutes.
Full back Jordan Williams looked to inject some pace from deep before Jack Dixon’s kick in behind was smashed back by Jayden Hayward.
Lively scrum half Rhodri Williams then found a gap and fed an onrushing Aaron Wainwright, but Benetton held firm under increasing pressure.
Hibbard and Nansen teamed up to unload a huge double tackle to win a penalty as Dragons looked to keep the high tempo up.
But they missed a huge chance as Jordan Williams glided past two men but the final pass to Howells found the turf with the line beckoning just metres away.
Benetton had done plenty of defending to keep the home side at bay and then struck themselves with two penalties from Allan around the half hour.
Dragons came strong again before the break with Dixon thundering into contact before a quick tap penalty was snuffed out as the Italians lead into the dressing rooms.
Henson struck an early penalty to cut the lead to a point at the start of the second half.
But back came Benetton and, after Jordan Williams raced back to dot down to stop a certain try, a five-metre scrum saw them apply pressure before Steyn burst over.
Seconds later it got worse as Benetton broke away down the left and quick hands fed Zanni to crash over for his second of the night.
Dragons sent on the reinforcements with a new front row and Josh Lewis in at fly half.
Rhodri Williams darted over with five minutes after and Lewis converted to set up a big finish. But there was to be no late dramas as the Italians held on.
02m Howells t Henson c 7-0
06m Zanni t 7-5
29m Allan p 7-8
33m Allan p 7-11
45m Henson p 10-11
52m Steyn t 10-16
56m Zanni t 10-21
75m R Williams t Lewis c 17-21
Dragons: 15 Jordan Williams, 14 Dafydd Howells, 13 Tyler Morgan, 12 Jack Dixon, 11 Hallam Amos, 10 Gavin Henson (Lewis 58), 9 Rhodri Williams; 1 Ryan Bevington (Harris 52), 2 Richard Hibbard (Dee 52), 3 Leon Brown (Fairbrother 52), 4 Brandon Nansen (Screech 52), 5 Cory Hill, 6 Lewis Evans (Taylor 68), 7 Aaron Wainwright, 8 Ollie Griifiths
Replacements: 16 Elliot Dee, 17 Brok Harris, 18 Lloyd Fairbrother, 19 Matthew Screech, 20 Huw Taylor, 21 Tavis Knoyle, 22 Josh Lewis, 23 Adam Warren
Benetton Rugby: 15 Jayden Hayward, 14 Ratuva Tavuyara, 13 Tommaso Benvenuti, 12 Alberto Sgarbi, 11 Monty Ioane, 10 Tommaso Allan, 9 Tito Tebaldi; 1 Fererico Zani (Appiah 14), 2 Hame Faiva (Makalara 53), 3 Tiziano Pasquali (Ferrari 48), 4 Alessandro Zanni (Fuser 58), 5 Dean Budd, 6 Sebastan Negri, 7 Braam Steyn, 8 Marco Barbini (Lazzaroni 68)
Replacements: 16 Engjel Makalara, 17 Derrick Appiah, 18 Simone Ferrari, 19 Marco Fuser, 20 Federico Ruzza, 21 Marco Lazzaroni, 22 Georgio Bronzini, 23 Tommaso Iannone
Referee: George Clancy