The Swede struck both goals as Milan won 2-1.
“Milan hadn't won the derby in four years, I was stuck at home for two weeks, so I was hungry and it showed," Ibrahimovic told Sky Sport Italia.
“I lost my sense of taste a little bit, but I had a swab every three days and nobody was going to stop me playing the derby."
“I'm disappointed that the penalty was saved, but the important thing is that the team won. I am the oldest in the squad, I feel a lot of responsibility and I like that feeling, as they all follow my lead and are hungry to win."
Ibra continued: “I know my level. After the injury, I went to America in order to feel alive. I told Jose Mourinho at Manchester United that I wasn't ready and didn't want to be a disappointment, so I went to America.
“Mino Raiola told me to return to Europe, they told me Milan needed me, so I came. I feel like a more complete player now than I was 10 years ago. If I had the fitness levels I did 10 years ago, nobody would stop me. Mind you, they can't stop me now either.
“I train hard, I play with experience and teammates who are ready to help out. I won't accept them taking their foot off the gas, in training or in a match. We must always train at 200 per cent."