It marked Pellegrini's first goal with the Azzurri yesterday.
“It's a great night for me and we won a game that was not simple, as Armenia are tough, especially on their own turf," Pellegrini told Rai Sport.
“Mkhitaryan had a great performance, he's an excellent talent and we can't wait to see him play for Roma.
“It's always an honour to represent Italy and I might need a while to get to learn these movements and tactics, but I am getting there.
“It's natural that there are lots of players who want to take a free kick from there, but I earned the foul and so I was first up. There are no problems."