The Gabon international, who signed for Arsenal from Borussia Dortmund in January, was cup-tied in the Europa League for Dortmund's European participation before the turn of the year.
Aubameyang told reporters that he has brushed off his "difficult" start to life at the Emirates and is raring to improve under Arsene Wenger.
"It was a bit difficult at the beginning but I am feeling better," the 28-year-old said. "I didn't play a lot in January so it was difficult to find the rhythm. Now I am feeling better. I work hard, I work a lot in the last weeks and I am happy because I feel better.
"I am really frustrated [in the Europa League] because the rules are a bit... I don't know how to say in English but I am disappointed because I can't help my team. That's life. I have to deal with it. I can't play every three days. When I was in Dortmund, I was playing every three days but now I play once a week or have a long time between games. It is not easy."
"It is a big win," Aubameyang said of Sunday's victory. "The team did very well and it is a great three points. We needed it. I think the fans are happy tonight which is really important."
Arsenal have a 2-0 advantage going into Thursday's return Europa League leg against AC Milan.