Inter's derby demolition of Milan sees Lukaku revel in Ibrahimovic rivalry

How different would this moment have felt, inside a jam-packed San Siro? How different would it have sounded? When Romelu Lukaku completed Internazionale’s rout of Milan in the Derby della Madonnina, burying a left-footed shot beyond Gianluigi Donnarumma for 3-0, would we even have heard what he had to say, above the din of 80,000 supporters?

“I’m the fucking best!” bellowed the Belgian as he ran to the corner flag, thumping his chest and cursing in both English and Italian. “Me! Me! I told you!”

Related: Inter take control of title race as Romelu Lukaku's stunner caps Milan derby win

Not even Zlatan Ibrahimovic could bring himself to dissent, casting his eyes down and offering resigned applause. This match had been billed as a showdown between them: two superstars whose arrival last season transformed a city’s footballing fortunes.

For the first time in a decade, Inter and Milan were squaring off as the top two teams in the Serie A table. Lukaku arrived as the division’s joint-leading scorer on 16 goals. Ibrahimovic was only two behind despite being making nine fewer appearances.

Their rivalry had defined recent editions of this derby. “There’s a new king in town,” tweeted Lukaku after scoring the final goal in a come-from-behind 4-2 victory over Milan last February. When Ibrahimovic struck twice to give his team the points in October, he countered that: “Milano never had a king, they have a GOD.”

Then came a scuffle in last month’s Coppa Italia quarter-final, when the two strikers had to be separated by teammates. Ibrahimovic was reported to have goaded Lukaku with taunts about his mother.

That incident remains under investigation by the Italian Football Federation, but became the subject, in the meantime, for a striking mural just outside San Siro. At a time when so much of the colour has been stripped away from football, the image of Ibrahimovic pressing his forehead into Lukaku’s chin cut through: a reminder that even empty stadiums can become a stage for iconic scenes.

There were more to come on Sunday. Fans of both teams sought to generate atmosphere outside the ground, thousands gathering with flares and flags to greet their teams in defiance of social-distancing laws. Inside, though, it was left to the players. Lukaku set out to make this occasion his own.

In the fifth minute, he thundered past Alessio Romagnoli down the right. Simon Kjær came across to block an initial centre, but that meant leaving Lautaro Martínez free in the middle. Lukaku recovered and swung a second delivery on to the head of his teammate, who thumped it in from close range.

Ibrahimovic did not shy from the challenge. This has been an indifferent season for Inter’s goalkeeper, Samir Handanovic, whose errors cost his team dearly in their Coppa Italia semi-final defeat by Juventus, but he would make a pair of stunning reflex stops after the interval to deny the Swede at point-blank range. He followed up with another good save after a shot from Sandro Tonali.

Related: Milan v Inter: the five best goals from the derby this century

Inter then produced a sensational team goal to extend their lead – nine different players touching the ball as they swept from one end to the other, Ivan Perisic playing the final square ball for Martínez to convert from six yards. The Croatia international would be credited with an assist on the next goal, too, though this was really all about one man.

Taking possession inside the centre-circle, Lukaku shed Franck Kessié and carried the ball 30 yards to edge of the penalty area, beating Romagnoli again before picking out the bottom left corner. His roar of vindication felt like something meaningful: that moment when a team that has scarcely challenged for honours since the departure of José Mourinho began to recapture its self-belief.

The magnitude of that goal for the title race was obvious. Victory moved Inter four points clear at the top, and the margin guaranteeing them the head-to-head tiebreaker over Milan on top.

The Rossoneri had stayed in the game admirably, but at 3-0 even their own manager, Stefano Pioli, seemed to acknowledge that the jig was up. Ibrahimovic was taken off soon afterwards, perhaps with an eye on Thursday’s Europa League second leg at home to Crvena Zvezda.

Scrutiny of the Swede’s actions in the coming days will be intense. Ibrahimovic is booked to play a role in the SanRemo music festival next week, a commitment he made before extending his contract for this season. The five-day long event takes place more than 150 miles away from Milan, and it appears impossible that he will be able to commute to train with his teammates.

The club were aware of this booking at the time of Ibrahimovic’s renewal, but few might have anticipated at that time that they would be challenging for the Scudetto. In fact, they had led this title race right from the start, all the way up until a surprise loss to Spezia in the previous round. For the player to depart now feels especially fraught.

Friday: Cagliari 0-1 Torino, Fiorentina 3-0 Spezia. Sat: Genoa 2-2 Verona, Lazio 1-0 Sampdoria, Sassuolo 1-1 Bologna. Sun: Atalanta 4-2 Napoli, Benevento 0-0 Roma, Milan 0-3 Inter, Parma 2-2 Udinese. Mon: Juventus v Crotone.

There will be no such distractions for Lukaku, producing his best in the most important games. His assist for Martínez’s opener began almost identically to one he provided against Lazio a week before, Romagnoli cast aside just as Marco Parolo had been. Lukaku scored two of his own against the Biancocelesti, sinking opponents who had previously won six straight matches. The magazine Sportweek described him as “a mountain that moves at the pace of [Italy’s high-speed] Frecciarossa train.”

Inter are more than one player. Martínez outscored Lukaku on Sunday, and the greatest aspect of this derby for his manager Antonio Conte might have been the performances of Perisic and Christian Eriksen: two players who so recently appeared not to fit in his plans. The former returned from a year on loan at Bayern Munich into an unfamiliar role at left wing-back but has thrived there over the past month. The latter finally seems to have carved out a role of his own.

Deployed variously as a No 10, a deep-lying playmaker and even a false nine since arriving from Tottenham last January, Eriksen has lately been playing as a something of a blend – lining up on the left of a midfield three but interpreting the position differently to Nicolò Barella on the opposite side. Where the Italian is a classic mezzala, running box-to-box and breaking the lines, the Dane roams a bit more widely and often tucks in alongside Marcelo Brozovic as a secondary distributor.

His adaptation remains a work in progress, and no one ought to be casting him as the star of this show, but he has become useful to Conte in a manner that was not true before.

It is another little detail in a big picture that suddenly looks very rosy. Milan are hardly out of sight, while Juventus, 11 points back, have two games in hand, but for the first time Inter are clearly in charge of this Scudetto race. Unlike their rivals, they also have no other competitions left to distract them.

More complicated troubles await on the horizon, with the club’s owners, Suning, reportedly seeking a bridging loan of close to €200m (£173m), at the same time as international investment is being discouraged by leadership in Beijing. On the pitch, though, Inter have found their swagger. In empty stadiums, they are starting to roar.