In a contest dominated by the Blues pack, forwards Kristian Dacey, Josh Turnbull, Gethin Jenkins, Manoa Vosawai and Macaulay Cook all crossed the whitewash for the visitors.
Full-back Rhys Patchell added eight points with the boot to help the Blues to maximum points from their opening two Challenge Cup fixtures.
But the Welsh region didn’t have it all their own way against Rovigo, who had been hammered 70-14 by the Exiles the previous weekend. The Italians haven’t won in Europe since 2008 but took a surprise early lead when outside half Luciano Rodriguez intercepted a pass and went under the posts from 40 metres.
The Blues got themselves straight back into it thanks to a try from hooker Kristian Dacey, before the visitors had a second ruled shortly after when Adam Thomas was judged to have knocked on. The Blues’ second try came after 24 minutes when captain Josh Navidi and put flanker Josh Turnbull under the posts.
Prop Gethin Jenkins got the Blues’ third after half an hour when all eight forwards were involved in a push.
Rovigo full-back Davide Farolini clawed six points back with two penalties either side of half-time before the Blues had another try disallowed by referee Laurent Cardona.
Blues number eight Manoa Vosawai secured the all-important bonus point try when he crashed over and a fifth try arrived 10 minutes before the end from Macaulay Cook.
Rovigo managed a second try with the final play of the game, captain Jean-François Montauriol going over after some excellent work by the forwards
