The hosts, on the other hand, got off to a losing start against Switzerland, with a chastening 3-1 home defeat coming after racking up a three-goal deficit after just 13 minutes.
When in-form Sassuolo forward Domenico Berardi thumped Italy ahead early on - in his third straight goalscoring start for the national side - against lacklustre Northern Ireland, it appeared as though the Azzurri were set for a cruise towards maximum points from their opening match in World Cup qualification.
However, even though last year's European Golden Boot winner Ciro Immobile drove in a second before the break, a spirited second-half showing from the visitors had Roberto Mancini's men on the back foot for long spells in Parma. Nonetheless, with that goal, Lazio front-man Immobile has been directly involved in seven goals in his last seven starts for Italy - scoring four times and providing three assists - and his strike proved enough to secure the win.
After the game, Mancini praised the verve and enterprise of his team in the first half, but acknowledged the lack of intensity in their passing after the interval.
The former Manchester City manager has, nonetheless, now won 16 of his 25 games in charge - with the Azzurri scoring 56 goals and conceding just 14 during that time - and is expected to sign a new, extended deal in the coming days. His side's victory also ensured that a remarkable unbeaten home record in World Cup qualifiers continued to a 56th game.
In a group featuring neighbours Switzerland, plus likely makeweights Bulgaria and Lithuania, an improving Italian outfit are expected to dominate the section and secure progress to Qatar - thereby easing the lingering pain of missing out in Russia last time around.
There will remain questions, however, over the makeup of Mancini's central defensive pairing. Though the masterful Juventus duo of Giorgio Chiellini and Leonardo Bonucci - who earned his 100th cap in midweek - helped keep another clean sheet at Stadio Ennio Tardini, both men have been beset by injuries during a troubled season for the Bianconeri - and neither is getting any younger, with the finals still nearly two years away.
With that in mind, Italy have been integrating a number of fresh faces into their experienced squad over the past few years, with exciting talents such as Juve's Federico Chiesa, the unfortunately injury-stricken Nicolo Zaniolo, in-form Inter man Nicolo Barella and Milan goalkeeper Gianluigi Donnarumma leading the way.
Now, having previously sealed a place in the final four of the Nations League next autumn - having topped a group including the Netherlands and Poland to get there - the Azzurri will expect to make it two wins from two to start their journey towards the first-ever Middle Eastern finals late next year.
Bulgaria committed a series of "childish mistakes" in a 3-1 home defeat to Switzerland in their previous fixture, according to head coach Yasen Petrov, who was no doubt embarrassed by the sluggish start his men made to a challenging qualifying campaign.
Three goals behind before even 15 minutes had been played at Stadion Vasil Levski, the Bulgarians rallied to concede no further goals and even netted a second-half consolation of their own, through Cagliari striker Kiril Despodov - currently on loan in his homeland, at Ludogorets. Also being dominated in terms of possession, with the Swiss having nearly two-thirds of the ball, it served as a severe reminder of their limited chances of progressing from Group C.
The Eastern European nation have fallen upon hard times in recent years, having won just two of their last 23 matches - the most recent of which was a 3-0 friendly win over Gibraltar last November.
As they have not qualified for the final stages since 1998 - four years after famously finishing fourth at USA 1994 - Bulgaria's drought on the global stage is likely to continue, as they prepare to face a well-oiled Azzurri machine this weekend ahead of a more moderate assignment in Northern Ireland next Wednesday.
There have already been a handful of withdrawals from Roberto Mancini's original 38-man squad for the three quickfire fixtures during this international break, after Roma's Bryan Cristante and Moise Kean of Paris Saint-Germain pulled out due to injury and Chelsea's deep-lying midfielder Jorginho was belatedly omitted because of a knee problem.
On Friday, Sassuolo strikers Francesco Caputo and Domenico Berardi, plus veteran defender Giorgio Chiellini, left the Italy squad and all three have been ruled out of the next two games.
Inter's Nicolo Barella only arrived at Italy's Coverciano camp just before the Northern Ireland game, due to his club side's COVID-19 outbreak late last week, so was replaced by Lorenzo Pellegrini at the Tardini. Both Barella and his Nerazzurri teammate Stefano Sensi could be set for starts in Sofia though, with Pellegrini and Manuel Locatelli perhaps sitting out.
The Serie A champions will be represented, however, by one of the few stars of their season, Federico Chiesa, who is expected to come into the XI in a wide attacking role, while Matteo Pessina and Azzurri new-boy Rafael Toloi - both of Atalanta - may also feature at some stage.
Despite his midweek goal and rich recent record of productivity while wearing the iconic blue shirt, Ciro Immobile could well be rested, allowing Andrea Belotti to take the central striker's role in Mancini's favoured 4-3-3.
Home manager Yasen Petrov included 10 uncapped players in his first selection as national boss, though regular fixtures such as experienced captain Petar Zanev and Brazil-born defender Cicinho should once again start in defence versus Italy.
Bologna prospect Valentin Antov began on the bench against Switzerland, but will vie for an opportunity to play against some familiar faces, with fellow Serie A man Andrey Galabinov, of Spezia, hoping to make the matchday squad this time out after being entirely omitted on Thursday.
The third player in the hosts' Italy-based trio, Cagliari forward Kiril Despodov, is again expected to shoulder the burden of creativity for a Bulgaria team that has often struggled in the final third.
Bulgaria possible starting lineup:
P. Iliev; Popov, Antov, Zanev, Cicinho; Malinov, Kostadinov; Delev, Chochev, Despodov; Galabinov
Italy possible starting lineup:
Donnarumma; Spinazzola, Acerbi, Bonucci, Florenzi; Sensi, Verratti, Barella; Insigne, Belotti, Chiesa
We say: Bulgaria 1-2 Italy
Though Italy are clearly a class apart from their next opponents in World Cup qualifying, coach Roberto Mancini may tinker with his team due to an intense schedule of three competitive games in a week.
Even if the visitors are not quick out of the blocks against their mediocre hosts on Sunday, there is an abundance of proven firepower for the Azzurri to call upon on the sidelines and they will surely seal six points from a possible six, ahead of another eminently winnable encounter with Lithuania in the coming days.