Argentina World Cup winner Lautaro Martinez and substitute Joaquin Correa made it 5-1 on aggregate before Benfica scored two late goals through Antonio Silva and Petar Musa.

Inter have lost four of their past five games in Serie A to drop out of the Champions League places, but Simone Inzaghi's side can now look forward to two mouth-watering matches against Milan - who knocked out Napoli on Tuesday - for a place in the final.

"It will be a special derby," said Martinez. "We all know what this game means, to play a Milan derby in the Champions League semi-finals.

"Happiness is the word, I'm so proud to represent this crest and this great club which is back to where it belongs."

Inzaghi, the first Italian coach to lead Inter to the semi-finals of the European Cup since Eugenio Bersellini in 1980-81, said his team have nothing to fear against Milan.

"We deserve this semi-final. It was a dream but now we're here and we'll play it big," he added.

Inter looked to be cruising when Italy midfielder Barella made it 3-0 on aggregate after creating space for himself inside the box before producing a wonderful curling finish.

But Benfica were not done and Norway midfielder Aursnes kept the tie alive with a powerful header.

The damage from the first leg was too much, however, as Martinez prodded home Federico Dimarco's cross before Correa netted two minutes after coming on.

To their credit, Benfica kept going and Silva made it 3-2 on the night before substitute Musa equalised deep into stoppage time.

However, it was not enough to stop Inter from booking their place in the semi-finals for the first time since 2010 - when they won the competition under Jose Mourinho.

• Reaction from Wednesday's Champions League games

Lautaro Martinez scored his first Champions League goal since 12 October

Inter and Milan set for epic showdowns

There were jubilant scenes at the end as home fans celebrated reaching the last four and a meeting with a team they know extremely well.

Inter and city rivals Milan have already met three times this season, with Inter emerging triumphant in one Serie A game and the Italian Super Cup, while Milan won in the league.

Now the rivals, who have been crowned champions of Europe 10 times between them, are gearing up for another two meetings to decide who goes through to the final in Istanbul on 10 June.

They promise to be two magical and intense occasions at the iconic San Siro, which was a cauldron of noise on Wednesday for Benfica's visit.

Despite the Portuguese club's late comeback on the night, the damage was done in the first leg last week.

Both Milan clubs will hope next month's games pass without incident after their last meeting on the Champions League stage, 18 years ago, was abandoned because of crowd trouble.

With Inter trailing 3-0 on aggregate, fans threw flares, one of which hit Milan's Brazilian keeper Dida on the shoulder. Play resumed for 30 seconds after a 20-minute delay before being abandoned, with Carlo Ancelotti's AC Milan going through to the semi-finals.

Inter have reached their ninth European Cup/Champions League semi-final

'This is going to go down in history'

Analysis: Italian football writer Vieri Capretta, speaking on BBC Radio 5 Live

"No Inter or AC Milan fan wanted this clash, because the pressure is going to be unbelievable.

"They've been great in cup competitions, especially Inter who have beaten Milan in the Super Cup this season. When the Champions League lights shine then it's a completely different matter for both of them.

"I think both are under a lot of pressure. This is going to go down in history regardless."