The Red Devils had to battle hard, playing with ten men for periods of the second half and all of extra time, before winning on penalties.
After the 1-1 draw and penalty win, Amorim spoke about his pleasure at the result.
He stated: "I think we play, especially in the first half, we play better (than) in the first game. We were better in set pieces today, more aggressive. We show different spirit, even with 10 men.
“We are improving on that aspect. I think we had a lot of difficulties in the beginning of the game to control the game with the ball and then we suffered, not big opportunities, but we suffered running after the ball, especially to switch of play, to win the first pressure of Arsenal. But then we can take in this moment, take the game to a different level when we talk about aggressivity. And that is a very good thing.
“We managed to score and then I felt in that moment we were able to improve with the ball, but with the (player) sent off (it) was really hard on us. And then we suffered all together, defending very well, with some opportunities from Arsenal. The players were really tired, but I felt since the first minute that today was our day. And I felt also a connection with our fans, our staff. It was a very good day for us in that aspect. We need to improve the way we play football."