Alexis Sanchez struck a 120th-minute winner as Inter beat Juventus with virtually the last kick of the game to claim their sixth Supercoppa Italiana title.
Lautaro Martinez scored from the penalty spot to cancel out Weston McKennie's opener in an action-packed first half.
After a dull second period, the game proceeded to extra-time and just when it seemed penalties were inevitable, substitute Sanchez popped up with a dramatic winner with seconds left to play, pouncing on a mistake from Alex Sandro.
READ ALSO: Chelsea ease past Tottenham into Carabao Cup final
Most of the drama was saved for the opening 45 minutes and it was Inter who applied all the early pressure, Lautaro scuffing a decent opening wide. The hosts also had an appeal for a penalty dismissed after a VAR check when Nicolo Barella took a tumble after a shoulder barge from Giorgio Chiellini.
Simone Inzaghi was left fuming by the decision and his pain was compounded when McKennie headed Juventus in front from Alvaro Morata's deflected cross in the 25th-minute.
But when Mattia De Sciglio made a clumsy tackle on Edin Dzeko 10 minutes later, the referee had no choice but to point to the spot.
Lautaro kept his cool, hammering the penalty into the top corner and leaving Mattia Perin, who was standing in for Wojciech Szczesny, with no chance.
Juventus started the second half brightly and may have edged ahead if Federico Bernardeschi was more clinical as he dragged a shot wide from inside the box.
READ ALSO: Real Madrid into Super Cup final after win over Barcelona
At the opposite end, Denzil Dumfries' bullet header was pushed onto the post by a fine one-handed save by Perin.
However, the pace of the game slowed as full-time closed in and a winner could not be found in 90 minutes.
Chances were at a premium in extra-time although alarm bells should have been ringing in the Juventus ranks when Sanchez only just missed the target with a header.
The visitors clearly didn't heed that warning. Alex Sandro was too lackadaisical when dealing with Federico Dimarco's cross, Matteo Darmian nipped in and Sanchez finished with aplomb to send the home supporters and bench wild.
Eurosport