Juve’s young cooks serve up a treat before Napoli take seat at top of table | Nicky Bandini

It took almost an hour for the first goal to arrive but once they started they just wouldn’t stop, Samuel Mbangula serving up the first dish of a Saturday night Serie A feast. A 6pm kick-off made Juventus-Milan the aperitivo before a dinner of Atalanta-Napoli.

How peculiar it sounds to frame a match between Italy’s most successful domestic side and its most prolific continental champion as the evening’s lighter course. Yet that is the reality: Juventus and Milan started this weekend outside of Serie A’s top four, while Atalanta and Napoli are contenders for the Scudetto.

The ingredients to both games were compelling. Milan defeated Juventus in the Supercoppa semi-final two weeks ago, before going on to beat Inter in the final, winning a trophy in their second game under new manager Sérgio Conceição. A repeat here could bring them right back into the fight for Champions League places.

Juventus, three points ahead at kick-off, had been trapped in a uniquely frustrating season of their own. Although unbeaten in Serie A, they had won only six of 19 matches. Pressure has been building on manager Thiago Motta, hired to great enthusiasm last summer after taking Bologna into the Champions League with innovative, position-swapping tactical schemes.

His Juventus team had shown glimpses of similar evolution, only to fade into something timid and stodgy. They have thrown away leads in eight separate games – including the Supercoppa loss to Milan. Fans had not seen them win at home in Serie A since 9 November.

Then came Saturday, and Mbangula. The Belgian winger, who celebrated his 21st birthday two days earlier, got a pair of gifts: first with the pass from Nico González, who froze the defence before releasing him into the left corner of the area, then with a deflection from Emerson Royal that wrongfooted the Milan goalkeeper Mike Maignan. But a goal was the least he deserved for a man-of-the-match performance.

If we wished to belabour our feasting metaphor, we might frame Mbangula’s emergence as evidence of Motta’s talent as a cook: an undervalued ingredient allowed the right recipe to shine. He did not even start regularly for Juventus’s NextGen side in the third tier last season, yet Motta stuck him straight into the first team to face Como on the opening weekend. Mbangula responded by bagging the first in a 3-0 win.

Or perhaps that does a disservice to the player, who has plainly applied himself to improving and whose ability to keep his eyes up in possession stands out. He has a different style to Kenan Yildiz, who lined up on the opposite wing on Saturday but has more often started ahead of Mbangula on the left, less likely to try taking on his man and more likely to look for the pass inside.

For Motta, there is another aspect. “He’s a kid who is helping so much in every situation,” said the manager at full-time. “He is always available, never out of the squad for injury or suspension.” That could sound like damning with faint praise, but Motta was sincere. It has at times been understated, amid valid criticism of their performances, how badly injuries have disrupted Juventus.

The cruciate ligament tear suffered by centre-back Gleison Bremer against Leipzig in October was devastating – Juventus kept clean sheets in six of the seven games he started before that – and the tip of the iceberg. You can count on one hand the first-team squad members who have been available for selection every week.

Mbangula’s opener on Saturday was followed quickly by a goal from Timothy Weah. On a day like this, when things go right, it is easy to see the potential in a group whose oldest starter was the 27-year-old Michele Di Gregorio in goal. Whether Motta is on the path to realising it might still be too soon to say. Milan, after all, did not resolve all their flaws by lifting the Supercoppa.

Napoli’s 3-2 victory over Atalanta in the later game was more immediately impactful. A loss would have trimmed their lead over the Bergamo club to a single point at the top. Instead, they widened it to seven.

Both results were on the table in a pulsating game. Mateo Retegui, making his first start in almost a month after a hamstring injury, showed the value of having a proper striker as he pivoted to blast home the opener after a quarter of an hour. Matteo Politano and Scott McTominay responded to have Napoli ahead by half-time.

After Ademola Lookman brought the scores back level with a dribble and finish in the 55th minute, Atalanta looked the more likely team to push on and win. But Napoli’s goalkeeper, Alex Meret, made a brilliant save from a Charles De Ketelaere header before Romelu Lukaku buried one of his own at the other end.

Napoli’s Romelu Lukaku (right) is congratulated by Scott McTominay during the 3-2 victory at Atalanta. Photograph: Xinhua/Shutterstock

If ever there was a game to convince you that Napoli really could win the league this season – for only the fourth time in their history – this might have been it: a force-of-will triumph away to title rivals who had beaten them 3-0 in the reverse fixture and not lost a league game since September. This, in the same week that the Partenopei’s supposed best player, Khvicha Kvaratskhelia, left to join Paris Saint-Germain.

Napoli caught some breaks. Giorgio Scalvini, a gifted young defender whose development has been upended by a string of injuries, was far too soft in his marking of Lukaku on the winning goal. But Antonio Conte’s impact is undeniable.

There are tactical aspects. Rote repetition of certain movements in training has been a key component of past successes and you can see the fruits of it again here in the way André-Frank Zambo Anguissa and McTominay alternate breaking the lines and reinforcing them.

And there are also less tangible ones. In an interview for Serie A’s YouTube channel at the start of the season, Anguissa talked about how Conte had got under players’ skin, saying: “He shows you that with your heart and your body there are no limits. There are things I would never have done before working with him that he has shown me are possible.”

Where Lukaku and McTominay’s stories have enjoyed greater international prominence, it is perhaps the Cameroon international who would most deserve consideration for Serie A’s MVP award if the season ended today: a relentlessly physical presence in midfield who dribbles less and passes more under Conte. Anguissa dominated his duels with Éderson on Saturday.

His two assists were essential to a sixth consecutive win, but the tests will keep coming. Next up for Napoli is a home game against Juventus, with whom Conte won a combined nine league titles as player and manager. Perhaps, by then, both teams might look different. Juventus’s starting left-back, Andrea Cambiaso, has been linked with Manchester City. Napoli may move to replace Kvaratskhelia.

There is a feeling these may be a frantic last few days of the transfer window for several Serie A sides. With such closely contested races for both the title and Champions League places, nobody wants to miss this chance to restock. Saturday’s football feast did not disappoint, but there are plenty more meals to come.