Having seen Inter extend their lead at the Serie A summit to six points earlier in the day, Napoli knew the importance of a win against the visiting Rossoneri.
Antonio Conte’s side came flying out the blocks, and their fast start was rewarded with a breakthrough inside 65 seconds when Giovanni Di Lorenzo’s long ball was expertly controlled by Politano, who swept clinically into the bottom corner beyond Mike Maignan.
Armed with the momentum, Napoli looked to press home their advantage, and after Frank Anguissa directed an audacious flick narrowly off-target, they duly doubled their lead in the 19th minute.
Billy Gilmour’s well-timed pass found Lukaku free in the box, and the Belgian talisman took one touch to compose himself before finishing coolly into the far corner.
Stunned by Gli Azzurri’s dominant start, Milan tried to gain a foothold in the contest as the first half progressed.
However, despite seeing plenty of the ball in the final third, clear-cut openings came at a premium, as Napoli maintained their two-goal advantage at the break.
The hosts continued to keep Sergio Conceicao’s men at bay during the early stages of the second period, with Santiago Gimenez curling wastefully over from the edge of the box.
As time ticked into the final 25 minutes, the Rossoneri spurned a glorious opportunity to halve the deficit when Gimenez saw a tame penalty saved by Alex Meret after Philip Billing had bundled into the back of Theo Hernandez in the area.
That miss looked to have cost Milan, but the visitors deservedly pulled one back with six minutes remaining, as Hernandez’s low delivery was tapped home by substitute Luka Jovic.
Having found the net in the final 20 minutes for the seventh time in their last eight league outings, Conceicao’s side went in pursuit of a dramatic leveller, but it ultimately proved a step too far as Napoli held firm under pressure to secure their first head-to-head home win in seven meetings.
Flashscore Man of the Match: Matteo Politano (Napoli)