The Gunners are into the quarterfinals after the 3-0 result saw them win the tie 4-3 on aggregate.
Aubameyang said: "I missed two chances to close the game but the most important thing is that we won and everybody is happy and proud."
On the physical nature of the game, he added: "Rennes were a bit nervous and angry as well but that's football sometimes and it can happen like that."
And on his goal celebration, Aubameyang says: "I needed a mask which represents me and that's the Black Panther. In Gabon we call the national team the Panthers!"