Italy made a confident start to their World Cup qualifying campaign with a comfortable 2-0 win over Northern Ireland in Group C on Thursday.
Northern Ireland rallied in the second half, forcing Italy goalkeeper Gianluigi Donnarumma into several saves, but the damage was done in the opening period, and the hosts saw out the win with ease.
"The first half was perfect because we scored two goals and could have scored more," Italy coach Roberto Mancini told Rai Sport. "In the second half we held the ball more and slowed down but after five months (without a game) it can be like this."
Up next for Mancini's Italy side are away games against Bulgaria on Sunday and Lithuania next week, while Northern Ireland face the United States in a friendly before hosting the Bulgarians.
Switzerland beat Bulgaria 3-1 away in the other Group C match played earlier on Thursday.
Italy have been revitalised under Mancini, coming into the game unbeaten in their last 22 matches - winning 17 - and the Azzurri dominated from the start.
Scoring for the third consecutive match for his country, Berardi set Italy on their way, finishing well in the 14th minute, before Immobile raced clear and beat goalkeeper Bailey Peacock-Farrell at his near post six minutes before the break.
The visitors, seeking a first win under Ian Baraclough, upped the tempo in the second half, with Donnarumma making a fine double save to deny Gavin Whyte and Michael Smith in quick succession.
"We were far too passive in the first half and sat off and gave them too much respect," Baraclough told Sky Sports. "We created chances in the second half and should really have given them a scare. That second half I cannot fault what we did."
Northern Ireland's Paddy McNair should have ensured a grandstand finish but blazed over late on as Italy built on their impressive Euro 2020 qualification campaign, where they won 10 out of 10 matches, and continue to look impressive under Mancini.