The midfielder struck in the week he inked a new five-year contract.
Pjanic said, "I am very happy to remain at this wonderful club, so I dedicate the goal to the fans, my teammates and the club. I have improved so much in recent years and it is thanks to my experience here.
“I thank everyone for their support and help."
Pjanic asked to be taken off during the second half, as he felt a twinge.
“I had a slight muscular problem, but nothing serious. I'll just take a day to rest and evaluate next week, as we need to make it three with a victory against Parma before the break for international duty."