Ian Keatley converted four penalties on his Six Nations debut to set holders Ireland on the way to an unspectacular 26-3 win over an uninspiring Italy.
Keatley kicked Ireland into a 12-3 lead to break Italy's resolve, then Conor Murray and Tommy O'Donnell scored tries after the hosts had hooker Leonardo Ghiraldini sent to the sin bin.
Italy finished with a flourish and Kelly Haimona thought he had scored a try, but it was ruled out because of the faintest of knock-ons by Sergio Parisse amid jeers from the Stadio Olimpico crowd.
Italy, who lost all their Six Nations matches last year, made too many elementary mistakes and never looked capable of repeating their 22-15 win of two years' ago.
On Friday, England extinguished early Welsh fire with clinical finishing, a brutal display of forward power and a dominant second half show to secure a 21-16 victory.
Striking the first blow in World Cup year, England held the hosts scoreless in the second half to quieten a noisy Millennium Stadium crowd and avenge a record 30-3 defeat two years ago in Cardiff.