Manolo Gabbiadini makes striking Saints start after cold shoulder at Napoli | David Hytner

It read a little like one of those Oscar acceptance speeches. Manolo Gabbiadini, the Italy striker, who had swapped Napoli for Southampton in a €17m (£14.6m) deal on the final day of the January transfer window, had a lot of people to thank and he would try not to forget anybody.

There was the city of Naples, the people there and, specifically, the fans of Napoli. There was the club’s president, Aurelio De Laurentiis, and the former coach, Rafael Benítez, under whom he had played for the first six months. There were the members of staff and, of course, his team-mates. But Gabbiadini did forget somebody in his Facebook post or, more precisely, he chose to ignore him.

There was no mention of Maurizio Sarri, who had taken over as the Napoli coach following Benítez’s departure for Real Madrid in the summer of 2015, and it was for good reason.

If it were not for Sarri, Gabbiadini might still be at Napoli and he might not be preparing to lead the line for Southampton against Manchester United in the EFL Cup final at Wembley on Sunday. Sarri’s arrival at the club in Italy’s deep south was a Sliding Doors moment for Gabbiadini and not only because he had enjoyed the most productive spell of his career under Benítez.

Sarri would become wedded to a 4-3-3 system and he did not feel he could use Gabbiadini in either of the wide attacking roles – for reasons that frustrated the player. And so Gabbiadini had to battle for the No9 spot but the problem there was called Gonzalo Higuaín. On the rare occasions that Higuaín did not play and Gabbiadini had an opportunity, he could not deliver. Sarri would trust him even less.

The difficult relationship passed the point of no return in the first half of this season, sending Gabbiadini towards Southampton and what has been an explosive start to his Premier League career. He lashed high into the net from a tight angle after 12 minutes of his debut against West Ham United, although the game would end in a 3-1 home defeat, while he scored two more in his second appearance – the morale-boosting 4-0 away win over Sunderland.

Gabbiadini had sensed opportunity at Napoli last summer, after Higuaín left to join Juventus, and he promptly scored four times in a 5-0 pre-season rout of Monaco. There were people in Naples who felt that the 25-year-old deserved a chance to show that he could succeed Higuaín but Sarri was not one of them. He signed Arkadiusz Milik from Ajax and started the season with him and, when the Pole was injured in October, he turned to Dries Mertens as a false nine. For Gabbiadini, the writing was daubed on the wall in great, ugly letters.

The Italian press were quick to pick up on Gabbiadini’s blanking of Sarri in his Facebook message but, in many ways, it shone a light on his personality. For the best part of 18 months, Gabbiadini had endured what he felt was unfair treatment at the hands of his coach.

Sarri started him in only 11 Serie A matches but Gabbiadini did not create any waves. He merely put his head down and tried to shine when called upon, normally as a substitute. When it was over, the Facebook post reflected his integrity and it made a point without any ranting because, if there is one thing that Gabbiadini does not do, it is controversy. He has never said a word out of place in public.

Sarri was asked about the episode and he refused to be drawn into an argument. But he did highlight how, under him, Gabbiadini had enjoyed the best goals-to-minutes ratio of his career – a remarkable statistic, given the player’s situation. During his two years at Napoli, Gabbiadini’s 25 goals in all competitions came at the rate of one every 124 minutes.

It was one of the reasons why there was such a scramble for him in January. Borussia Mönchengladbach, Marseille, Milan, Fiorentina and West Bromwich Albion all wanted Gabbiadini, while it is worth remembering that Everton saw a €23m bid for him turned down last summer. In January 2016, Wolfsburg had failed with a €27m offer.

De Laurentiis has always loved Gabbiadini and it was with a heavy heart – and after protracted negotiations – that he sold him to Southampton. Although the fee could rise to €20m based on goals and appearances, De Laurentiis fears that Southampton have got a bargain.

The outlay took the total spend on Gabbiadini, in fees, to €42.5m. After beginning his career at Atalanta, he was involved in a series of co-ownership deals, the most eye-catching of which saw Juventus buy 50% of his rights from Atalanta in 2012 for €5.5m. Co-ownership of a player is now banned in Italy.

It was in line with Juventus’s drive to control the best young Italian talent, but Gabbiadini would not play a single game for them. They loaned him to Bologna, where he spent an important year under Stefano Pioli, learning to play as a wide attacker before he developed further under Delio Rossi and Sinisa Mihajlovic at Sampdoria. They had entered into a co-ownership agreement with Juventus and, when Gabbiadini signed for Napoli in January 2015, Sampdoria split the €13m fee equally with Juventus.

Rossi was the man that had pushed to take Gabbiadini to Sampdoria – he knew that he needed a replacement for Mauro Icardi, who would move to Internazionale that summer – and he considered him to be an “exceptional talent”.

“The most incredible thing about Gabbiadini is how he trains,” Rossi says. “He is an incredible professional, a little soldier. One time, I told him: ‘You know, you can leave when training has finished.’ He just smiled and said: ‘I like to arrive first and leave last. I want to get better all the time.’ It is that hunger to always improve that really stood out.”

Gabbiadini has played as a No9 or off the flanks – although not under Sarri – and he has been forced to adapt his game because, in an ideal world, he would work as a second striker. There are not too many teams who play with one of those these days and it is debatable whether Claude Puel, the Southampton manager, will partner Gabbiadini with Charlie Austin, when the latter recovers from injury.

What is plain is that Southampton have a striker with the ability to play between the lines or on the shoulder of the last defender. Gabbiadini’s movement was sharp and intelligent against West Ham and Sunderland, while his technique, particularly with his left foot, further marked him out.

“We’ve seen straight away that his finishing is top drawer but he can come in and link the game, as well,” Nathan Redmond, the Southampton winger, says. “He’s struggling with the language barrier, although we have an Italian physio who does a lot of the translating. He’s still tactically aware and understands what we want to do here. Three goals in two games is a great return and the language of football is universal.”

Gabbiadini scored in each of his final three appearances for Napoli, meaning that he is now on a run of six goals in five matches. He has often scored in streaks, with his four in five and six in nine standing out from his half-season under Benítez. When he is hot, he is hot and it is fair to say that this is a player who responds to being made to feel important.

“He needs to be appreciated,” Rossi says. “If you don’t back him, it upsets him. It’s his way of being. He is a very introverted character, who doesn’t like to talk a lot. But you have to respect that. He had problems at Napoli because he did not play in his role. To me, he is not a lone striker. He has to play together with another striker or, possibly, in a wider role.”

At Southampton, Gabbiadini simply wants to play and he will continue to be consumed by two things: the numbers and the hard work. He scored 12 goals for the Italy under-21s – only Alberto Gilardino and Andrea Pirlo have more – and he has gone on to win six caps at full international level. The potential has long been tantalising. The challenge for him is to realise it.