The win gives Inter a good chance to set up an all-Italian semi-final against Serie A leaders Napoli or city rivals AC Milan.
Inter, who beat another Portuguese side, Porto in the last 16, hosted Benfica at the San Siro in the second leg on Wednesday, 19 April.
Benfica defender Antonio Silva said he believes his team can go to Milan and score three to stage a comeback.
“We deserved more and we had the opportunity for it, the fair result was a draw,” Silva told Portuguese broadcaster XI.
“It is the first half of the tie. We are going to do everything we can in Milan and we need to score at least three goals to win and move on.