Romelu Lukaku scored an 82nd-minute penalty as Inter Milan put themselves in a strong position to advance to the semi-finals of the Champions League after a deserved win away to Benfica.
Nicolo Barella’s downward header gave Inter the lead in the quarter-final first leg in Lisbon.
Benfica struggled to dictate play in front of their own fans as Inter produced a defensive masterclass in Lisbon.
Rafa Silva was denied by Andre Onana’s first-half save before Inter’s Netherlands defender Denzel Dumfries produced a crucial block from close range as Benfica pushed for an equaliser.
The Italian visitors wrapped up a solid win when substitute Lukaku, on loan from Chelsea, scored from the spot after former Inter player Joao Mario handled.
Premier League referee Michael Oliver awarded the penalty after watching the incident on the pitch side monitor, with replays showing the ball struck the side of Mario’s head before hitting his hand.
Simone Inzaghi’s side will fancy their chances of finishing the job in front of their own fans in the return leg on 19 April (20:00 BST).
Inter arrived in Portugal’s capital on the back of a poor run of form after failing to win any of their past six games.
But they took advantage of a hesitant Benfica to take a firm hold of the tie.
Barella’s goal came after an excellent cross by Alessandro Bastoni, with the Italy midfielder heading it back across the keeper and into the net.
It was Inter’s first attempt on target but Benfica keeper Odisseas Vlachodimos prevented further damage by saving from former Manchester United and Arsenal player Henrikh Mkhitaryan.
This was Benfica’s 13th European game of the season after starting their Champions League campaign at the third qualifying round stage back in August.
But they did not create enough and face a mammoth task to turn the tie around after Lukaku wrapped up victory.
The Belgium forward had missed out on a starting place to 37-year-old Edin Dzeko but made an impact from the spot after beating the keeper for pace and power.
There was still time for Benfica to reduce the deficit but Goncalo Ramos’ 89th-minute attempt was kept out by Onana on a memorable night for Inter.
“We cannot think that we are already in the semi-final because we are not,” Onana said.
“We still need another great game like today’s next week. I said that we had to come here and play without fear because we could win – we did just that.”