Last year’s Supercoppa champions Inter had the better of the first half, as Federico Dimarco, who scored in last year’s final, almost opened the scoring by volleying just wide inside 15 minutes.
Half-chances for Hakan Calhanoglu and Henrikh Mkhitaryan followed swiftly, before top scorer Lautaro Martinez eventually tapped the ball in the net, only for the goal to be ruled out for an offside in the build-up. Napoli rarely threatened, with only Khvicha Kvaratskhelia really showing signs of potentially hurting Inter’s defence.
The Georgian had a chance to give the Scudetto holders the lead early in the second half, but his curling effort was parried away by Yann Sommer.
However, things turned for the worst for Napoli, who saw Giovanni Simeone sent off for a second bookable offence on the hour-mark, going from hero to zero after scoring the opening goal of the semi-finals.
Unsurprisingly, Inter then dominated proceedings, as Marcus Thuram mis-kicked from close range after being picked out by Benjamin Pavard. Moments later, the French duo combined again, but Thuram could only spill the ball over at the back post after Pavard flicked on a corner.
Napoli continued to hold out for penalties, as Inter boss Simone Inzaghi turned to his bench for attacking inspiration. Two of those substitutes, Alexis Sanchez and Marko Arnautovic combined with five minutes to go, with the latter seeing his close-range effort spilled by Pierluigi Gollini.
More time ticked by, and it looked like the game would be decided by a penalty shootout, but in injury time, Martínez broke Napoli hearts and won the cup for Inter with a deft finish into the bottom corner – making sure he scored in three consecutive Supercoppa Italiana final wins for the Nerazzurri.
They became only the second-ever side to win three in a row after rivals AC Milan, and overtook them for total victories with eight now to their name. However, it is back to the drawing board now for Napoli, who have still yet to win three consecutive matches over all competitions this season.
