Dragons (7) 22
Benetton Treviso celebrate a landmark victory
Tries: Charvis, Bearman, R Thomas
Cons: Sweeney (2)
Treviso (8) 24
Tries: De Gregori, Kingi
Pens: Goosen (4)
Marius Goosen's penalty in the last move of the game gave Benetton Treviso the win at Rodney Parade and all but ended the Dragons' slim Heineken hopes.
Treviso prop Nicolas De Gregori got the opening try from short range, Colin Charvis replying with a fine score.
Joe Bearman and Dion Kingi exchanged tries, before Rhys Thomas crossed.
Goosen's boot got Treviso back in front, Ceri Sweeney looked to have snatched it with a drop-goal, but then came Goosen's calm final kick.
The victory was Treviso's first on Welsh soil, but they also have next to no hope of making the quarter-finals.
The match had enjoyed a stormy build-up, the Dragons' dramatic fightback for a 33-35 win in Treviso last week having been followed by the Welsh side's players Rhodri Gomer-Davies and Thomas breaking a curfew and getting arrested following a nightclub fracas.
The pair were threatened with internal disciplinary action this week, but both started in Newport.
You can't win European games like that
Dragons coach Paul Turner
Centre Goosen galvanised the visitors after last week's defeat, though, and was rewarded with an early penalty followed by De Gregori's score.
The prop was then sin-binned for illegal use of the boot and, almost immediately, centre Gomer-Davies went through a hole on the Treviso 10-metre line on the left.
After making ground he fed wing Martyn Thomas who found Charvis, the skipper able to stretch to put the ball on the opposition line under the posts, making Sweeney's conversion simple.
Man-of-the-match Bearman picked and drove over from a close scrum and Sweeney converted, but Goosen soon countered with a second penalty.
In two years time we want to compete in the Heineken Cup
Treviso coach Franco Smith
Dragons prop Adam Black was sin-binned for holding down at a ruck and, moments later, number eight Kingi romped through a gap 15 metres out to put Treviso back in front.
The Dragons were not quite finished as the final 10 minutes approached.
Thomas put his side back in front with a drive over the line which put the Dragons a solitary point ahead at 19-18, but Goosen slotted a third penalty.
Sweeney continued the dramatic finale by landing a drop goal from 30 metres with two minutes left.
However, Goosen's fourth penalty success gained revenge for the Italians.
Dragons coach Paul Turner:
"They were a physically big side and tended to play in the right areas. We could not break them down and, although we got a lot of things right, we got as many things wrong and that was the story of our afternoon.
"They had a good line-out and you could probably see near the end that, as we did not kick it out far enough, they got their driving going from the line-out and got the penalty.
"As many things that were good from us, there were as many bad and you can't win European games like that.
"I don't think we ever got control of the game even when we dropped the goal to possibly win it - I think there was four minutes left on the clock then - which was the same as last week.
"In those last magical four minutes, we don't seem to be composed enough to go on and win those games. So it is disappointing but we've played a good European side.
"People may think we have come up short and we are extremely disappointed not only for ourselves but also four our supporters."
Treviso coach Franco Smith:
"I must say I'm very happy. In the end, it could have gone either way as both sides played some good rugby.
"We are growing as a team and we are a new group of players. We have new ideas and, in two years time, we want to compete in the Heineken Cup so we are going to use this experience to go forward.
"Our aim at the moment is to earn the respect of others in Europe and what helps us is that every game we play is a growing phase.
"We have our own objectives and winning is not always the objective of the game."
Dragons: K Morgan; M Thomas, P Emerick (A Smith 58), R Davies, R Fussell; C Sweeney, A Williams (W Evans 58); A Black (H Gustafson), S Jones (B Daly 44), R Thomas, L Charteris (A Jones 58), M Owen, J Bearman, C Charvis (captain), R Parks (H Gustafson (63-68).
Treviso: B Williams, L Borges, M Horak (S Orlando 69), M Goosen, B de Jager (M Muccignat 36-44), A Mercato, F Semenzato (N Mauger 63), N de Gregori, F Sbaraglini (D Vidal 50), M Barbieri (M Muccignat 49), A Pavanello (S Palmer 44), C van Zyl, R Berbieri, D Kingi, H Louw (N Picone 79).
Referee: Andrew Small (RFU).