The veteran hit a stunner as Inter won 2-0 to setup a semifinal against AC Milan.
The Austria international later told Sky Italia: "What it is worth to Inter is also worth to me. The most important thing is that we won the match, we are very happy."
On their top of the table clash with Napoli, Arnautovic also said: "To win, we are Inter and we go with this objective wherever we go. Napoli is strong and must be respected, but we will go there to try to win."
And on a derby for the semi-finals, he added: "Let's think about Saturday, it's still a long way to go to the derby."