Gigi Buffon’s Parma pushed Inter to the limit at San Siro in the Coppa Italia Round of 16, leading until the 88th minute when Lautaro Martinez equalised and Francesco Acerbi’s cheeky header won it in extra time.
They will now go on to face either Atalanta or Spezia in the quarter-finals.
The holders began the defence of their title by hosting Serie B outfit Parma, including Buffon just 18 days before his 45th birthday, here making his 50th career appearance at San Siro. Romelu Lukaku, Marcelo Brozovic, Hakan Calhanoglu and Nicolò Barella were out injured, as Simone Inzaghi rotated the squad.
Danilo D’Ambrosio made a howler playing out from the back in the opening minutes and was fortunate Franco Vazquez didn’t take full advantage with a shot saved by Andre Onana.
Roberto Gagliardini skimmed the base of the near post on a smart Robin Gosens assist and Dennis Man went off with an early injury.
However, his replacement opened the scoring, as Stanko Juric hit a scorcher into the top corner from outside the D, which took Onana by surprise.
It was nearly 2-0 on the stroke of half-time, as Adrian Benedyczak hit a ferocious volley from the edge of the area that Onana flew to palm away.
Denzel Dumfries pulled back from the right for Henrikh Mkhitaryan, who slipped at the crucial moment from just inside the box, while Adrian Bernabè wasted a counter-attack with an over-hit pass for Sohm, allowing Raoul Bellanova to sprint across and cut him off.
Buffon got his gloves to a glancing Edin Dzeko header on the corner as it turned into a siege, but still one without shots on target.
Their first genuine attempt was the equaliser on 88 minutes, as Kristjan Asllani floated a ball over the top for Dzeko, but it was cleared by Botond Balogh only as far as Lautaro Martinez on the edge of the box for a shot that went into the top corner with a deflection off Yordan Osorio.
Inter thought they’d won it in stoppages, but Buffon just 18 days shy of his 45th birthday got down so quickly to deny Dzeko.
It went to extra time and Onana used his stomach to parry Drissa Camara’s strike at the near post and was right behind a Valentin Mihaila rocket.
Inter almost threw it away when Gagliardini’s terrible sideways pass was intercepted by Antoine Hainaut, whose angled drive skimmed the far post with Onana beaten.
Federico Dimarco’s volley was off target and Bellanova’s header straight at Buffon from a Dzeko cross, but Inter did turn the game around eventually.
Dimarco showed great skill to take down a long Asllani ball over the top, his taut cross was beaten away by Buffon, but Francesco Acerbi was very smart to take the header first time from the edge of the box, looping it under the bar, knowing the goalkeeper was off his line.
Inter 2-1 Parma aet
Juric 38 (P), Lautaro Martinez 88 (I), Acerbi 110 (I)