Treviso replied through a Brendan Williams breakaway try and three penalties from fly-half Andrea Marcato.
It will mean another start for winger Andrew Maxwell, who notched three tries against Treviso last weekend.
The Welsh region's performance did not reach the heights of the previous weekend's 68-8 win over Treviso.
Treviso staged a second-half comeback with a try through Benjamin De Jager and two penalties from Maruis Goosen.
Lucas Borges and Alberto Sgarbi tries, plus Marius Goosen's boot, put Treviso ahead only for Sweeney to strike.
Glasgow Warriors' Friday Magners League match against Treviso is another sporting event to fall to the cold snap.
Treviso prop Nicolas De Gregori got the opening try from short range, Colin Charvis replying with a fine score.
"Ciak Junior" is broadcasted every year, in parallel to the Festival in Treviso, on Sunday mornings on Canale 5.
The victory was Treviso's first on Welsh soil, but they also have next to no hope of making the quarter-finals.
Instead, coffee companies such as illycaffe and Hausbrandt, a rival based in Treviso near Venice, have developed electronic detection systems.
But Treviso launched a stunning comeback at the Stadio Comunale di Monigo and captain Goosen was at the heart of it.
The Swansea-based side will host Italian champions Benetton Treviso at the Liberty Stadium in their opening home fixture on Friday, 10 September.
Tries from Colin Charvis, Rhys Thomas and Rhodri Gomer-Davies gave Dragons a 25-13 lead at half-time, Nicolas De Gregori replying for Treviso.
Despite the heavy defeat, it was Treviso who got the first points of the game with Kristopher Burton sending over an early drop-goal.
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.
But Treviso responded with their first try of the game when full-back Brendan Williams finished off his own break and Burton added the two points.
Italy have named Kristopher Burton at fly-half, and he will line up alongside Benetton Treviso team-mate Edoardo Gori, who wins his third cap at scrum-half.
Treviso far more competitive at the break-down in the second half and dominated the territory in the third quarter, scoring two penalties in the process.
"We've built up quite a rivalry with Leicester in our short existence, " said Humphreys, who then face Perpignan and a double header with Benetton Treviso.
Treviso's economy is diversified, however, and jobs are not yet an issue in Carpi, where neat industrial estates and the city's shops exude well being.
Replacement Alberto Sgarbi then juggled with the ball before getting it under control to touch down in the corner as Treviso reduced the deficit to 43-15.
Fly-half James Hook converted Wyn Jones' and Thomas' tries, while Treviso belatedly got on the scoreboard through a 30th-minute penalty from Hook's opposite number Andrea Marcato.
Crane got his hat-trick after the break and Thomas Waldrom added a sixth before two Treviso tries, but Hamilton, Manu Tuilagi and Steve Mafi crossed late on.
Argentine Lucas Borges and Australian full-back Brendan Williams combined to send Treviso's South African wing Thomas de Jager over in the left corner for a consolation try.
Waldouck stressed that Waters - who has left to join Treviso in Italy - would be missed just as much as Dallaglio after 10 years with Wasps.
It was not until first-half injury time that the home crowd had something more to cheer when prop De Gregori steamed over to hand Treviso a lifeline.
Kevin Morgan scooped up possession midway inside Treviso's half and beat two men before Paul Emerick sent captain Charvis over after 18 minutes, Sweeney adding the conversion.
The Scarlets go to Perpignan on Sunday whereas the Tigers host Italian side Benetton Treviso at Welford Road, giving them a major opportunity to underline their European credentials.
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.
Alberto Sgarbi is included after a strong start to the season with Treviso, and he will start at inside centre, with Andrea Masi moved out to the wing.
应用推荐