AC Milan reached the Champions League semi-finals for the first time since they won the trophy 16 years ago thanks to a first-half goal from Olivier Giroud at Napoli.
Giroud’s goal secured a 1-1 draw and 2-1 aggregate win despite a barrage of pressure on Tuesday.
Napoli battled until the end but could not break down the resilient Milan defence until striker Victor Osimhen equalised three minutes into stoppage time with a bullet header.
But it was too late as the referee ended the match seconds later.
Seven-time European champions Milan will now face either Inter Milan or Benfica, who meet on Wednesday at the San Siro with the Italian side leading 2-0 from the first leg.
Milan coach Stefano Pioli said he would welcome a semi-final against their city rivals.
“It would look like that, as Inter won the first leg so well. These will be another two difficult, exciting and wonderful clashes in the Champions League.
“We’ve done a great deal and don’t want to stop now,” he told reporters.
This was the third meeting between Milan and Napoli in 16 days, with Pioli’s visiting side having claimed a 4-0 victory against the runaway Serie A leaders on April 2.
After Milan won the quarter-final first leg 1-0, Napoli pushed for the opening goal from the start as the visitors were forced to defend deep against an attacking onslaught.
“I think the small advantage of the 1-0 in the first leg helped us in one sense and blocked us in another,” Pioli said.
“We chose, considering Osimhen was there, to sit a little deeper and not allow him those spaces where he can be devastating.”
Milan struggled in a raucous atmosphere, with loud boos resounding throughout the stadium every time they gained possession.
But they held off an aggressive Napoli side for most of the match with an impressive defensive display.
Milan had the chance to take the lead with a penalty after 22 minutes after Mario Rui clattered into Rafael Leao but goalkeeper Alex Meret dived to stop Giroud’s low strike.
Meret saved Napoli again when he parried Giroud’s attempt inside the box with his foot five minutes later.
As a result of the intense pressure exerted by the hosts, Milan were able to exploit the holes in the home defence and went ahead through Giroud just before the interval.
Leao sprinted with the ball from his own half past the Napoli rearguard before rolling it across to Giroud who slotted home from close range.
Napoli had a glimmer of hope eight minutes from time when Fikayo Tomori handled the ball inside the box, but Khvicha Kvaratskhelia’s penalty was saved by Mike Maignan.
Osimhen was shackled all night until his added-time header but it came too late for Napoli and their disappointed fans.
“I saw an enormous sacrifice from my players, we trusted each other and our way of playing football to overcome a great Napoli side that caused us problems over both legs.
“We won it with heart, energy and belief,” Pioli said.
Napoli, who were in the last eight for the first time, are in a mini-slump without a victory in their last three matches in all competitions.