The Gunners were down a goal and a man at home against Villa, but Aubameyang put the icing on the cake of a 3-2 comeback.
Aubameyang wrong footed Villa keeper Tom Heaton.
Leno, who had a great view of the free kick from his goal, spoke about it with the club's official website after the game.
"I had the perfect view," Leno said.
"From behind I could see the shot, it was a knuckle-ball, I think and it's very difficult for the goalkeeper because he didn't see the ball and it was a fantastic goal.
"He's unbelievable and the goal was also unbelievable. I think he's very important for us because he scoring almost every week, and getting important goals for us too."