Roberto Mancini and Leonardo Bonucci acknowledged there is room for improvement from Italy, despite kicking off their 2022 World Cup qualifying campaign with a routine 2-0 win over Northern Ireland.

Domenico Berardi scored for the third international running and Ciro Immobile doubled the Azzurri's lead before half-time in Thursday's Group C clash at Stadio Ennio Tardini.

After managing five attempts on target in a dominant first half, however, Italy dropped off in the second period and failed to test Bailey Peacock-Farrell on a single occasion.

Northern Ireland went close to pulling one back through strikes from Gavin Whyte, Michael Smith and Steven Davis, while Paddy McNair blazed over from a good position late on.

The victory was Italy's fourth in a row without conceding and extended their unbeaten run to 23 matches.

But Mancini was not pleased with what he saw in the second half of the game in Parma, which he put down to the lengthy break between matches for his side.

"After four months, the first half was excellent and we should've scored more goals," he told Rai Sport.

"We'll have to review the second half with the team, because we must do better than that. The first half was perfect and we should've had more goals.

"Perhaps we started to take a few too many touches after the break and the ball moved slowly, but that can happen after four months of not seeing each other.

"We could've won by a bigger margin in the first half, but we knew Northern Ireland were a physical side who could cause us problems. We made too many mistakes.

"The ball can go long at times, especially when we're pressed like that and the opposition are defending in numbers."

Italy's possession count dropped from 72.6 per cent in the first half to 59.6 in the second and they regularly gifted the ball to their opponents.

Bonucci, who became the eighth player to win 100 caps for Italy with his appearance on Thursday, accepted lessons can be learned from the contest.

"It's important that we kept a clean sheet, even if we made a lot of mistakes in the second half and need to improve, especially when we're in possession," he said.

"But what I've always liked since Mancini took over is the attitude. We face everyone without fear, we keep our nerve and go out there to win every game.

"It means there's a lot of hard work behind it, from the players and the staff, because the ideas are clear and we drill them in very quickly.

"The young players here have a lot of talent, along with the spirit of sacrifice and hard work, so these are the results."

With his 14th-minute strike in Parma, Immobile has now been directly involved in seven goals in his last seven starts for Italy - four goals and three assists.

It was a rare goal from open play, however, and the Lazio striker celebrated wildly at the empty ground.

"I felt a weight off my shoulders because I hadn't scored from open play for a year and a half in the Italy shirt," he told Rai Sport.

"I slipped on the first chance, the goalkeeper was there on the second, so I was feeling frustrated and let it all out after the third chance went in.

"Having competition for places only makes you more determined to find the net and help the team. [Andrea] Belotti scored last time, I got the goal this time, so there needs to be more faith in this Italy side."

Italy join second seeds Switzerland on three points at the top of Group C and travel to Sofia on Sunday to face Bulgaria in their next qualifier.

Mancini, who is one of only three coaches to stay unbeaten in his first 15 home matches in charge of Italy after Enzo Bearzot and Marcello Lippi, hinted he will heavily rotate his side for that match.

"We need to change something. We need some fresh players," he said at his post-match news conference. "Nothing should change on the pitch, even if we were to alter five players."

Italy kicked off their 2022 World Cup qualifying campaign with a straightforward 2-0 win over Northern Ireland at Stadio Ennio Tardini on Thursday.

The Azzurri entered the contest without defeat in 22 games and that unbeaten run never looked under threat from the moment Domenico Berardi opened the scoring 14 minutes in.

Ciro Immobile doubled the lead for Roberto Mancini's in-form side seven minutes before half-time and the hosts saw out victory despite an improved Northern Ireland display in the second period.

The win moves Italy level on three points with second seeds Switzerland - 3-1 victors against Bulgaria earlier on Thursday - at the top of Group C after their opening fixtures.

Northern Ireland were given an early warning when Immobile chested down Alessandro Florenzi's floated pass and fired straight at Bailey Peacock-Farrell, but there was no stopping Berardi's strike three minutes later.

The Sassuolo forward was played into space down the right by Florenzi and lifted the ball away from Peacock-Farrell at his near post to become the first Italy player to score in three successive matches under Mancini.

Italy continued to patiently probe away and had a second goal through Immobile's drive past Peacock-Farrell - again at the visiting keeper's front post - after being played in by Lorenzo Insigne on the counter.

Gianluigi Donnarumma was called into action twice in quick succession 11 minutes into the second half to keep out Gavin Whyte's volley and Michael Smith's follow-up attempt.

Milan stopper Donnarumma was the busier of the two goalkeepers in the second period, with Craig Cathcart and Steven Davis the next players to be denied, but there was to be no way through as Mancini's men triumphed again.

Lazio can win Serie A's Scudetto race this season according to Christian Vieri, who lauded Simone Inzaghi's "amazing" team.

Spearheaded by highly rated head coach Inzaghi, talisman Ciro Immobile and star midfielder Sergej Milinkovic-Savic, Lazio are once again challenging in 2020-21.

Lazio can move to within six points of top spot with victory over second-placed Inter on Sunday as they prepare for a blockbuster Champions League last-16 tie against holders Bayern Munich.

Inzaghi has renewed Lazio's fortunes since taking charge in 2016, guiding the capital club to Coppa Italia (2019) and Supercoppa Italiana (2017 and 2019) success. The Biancocelesti had not celebrated silverware since 2013.

Ahead of the Inter showdown, Lazio have found the net in each of their past 17 Serie A games – they last went on a longer streak in October 1994 (18).

Lazio have also gained the most Serie A points in 2021 (19). They are the only unbeaten side (W6 D1) – having also conceded the fewest goals (four, level with Genoa) since the turn of the year.

Vieri spent a year with Lazio in 1998-99 – scoring 14 goals in 28 appearances under Sven-Goran Eriksson as the club won the UEFA Cup Winners' Cup and Supercoppa Italiana alongside Alessandro Nesta, Pavel Nedved, Marcelo Salas, Sinisa Mihajlovic and Dejan Stankovic before a then-record move to Inter – and he hailed the work of Inzaghi.

"He has been there for four years. You can't change coach every year," ex-Italy striker Vieri told Stats Perform News. "Coaches need time. All the teams that are changing every year aren't doing well.

"Lazio are doing amazing. They have an amazing director – [Igli] Tare, fantastic. They have big players at Lazio.

"Lazio are a fantastic team. They played amazing football. In the Champions League and qualified very easy.

"Lazio are there to win everything. Lazio can win the Scudetto, you never know. Let's see what happens in the Champions League. Anything can happen, but they're doing amazing."

Lazio have not won the Scudetto since 1999-2000 – Inzaghi was part of that triumphant team as a player – but threatened to end their drought last season.

They were only a point adrift of Juventus when the league was suspended due to the coronavirus pandemic in March last year.

But when the 2019-20 campaign resumed, Lazio stumbled and eventually finished third – four points behind Juve as the Turin powerhouse claimed a ninth consecutive Serie A crown.

"Everyone stopped playing, not only Lazio. The thing is, when you play and you don't need to win the Scudetto, you play with no pressure," the 47-year-old Vieri explained.

"When they say to you, there's 8-10 games to go and we have to win all eight, and tomorrow we have to win, it changes. You stop sleeping. You're nervous because you have to win.

"One thing is winning the game and no one says anything – you're second or third but no one expects you to win. But when they say there's five games to go and you have to win all five, that changes everything.

"When they started again after COVID-19, they had to win the last six or seven games and didn't do that. Juventus are used to the pressure. That's how it is."