The victory over the Azzurri kept Wales in with a chance of the Six Nations title, with Roberts branding their scrum "outstanding".
"Our scrum was outstanding. Adam Jones was magnificent, as were Gethin Jenkins and 'Hibbs' (hooker Richard Hibbard). I take my hat off to the forwards - they worked so hard," he told reporters following the match.
"Tight games are often decided by things like a bounce of the ball, but we got our just reward."
England currently top the Six Nations table.