"You cannot give Juventus the opportunity to score certain goals," Petkovic told Sky Sport Italia.
"We need to be sharper and more clear-headed both in defence and attack, because we had our chances too.
"We went too deep and allowed too much space to the Bianconeri, a very strong side who keep the ball well and burst through with their midfielders. We should've been tighter and more compact.
"Now there is the break for international duty and we must reflect on how to avoid certain situations."
For the big stories and the banter follow us on Twitter: @tribalfootball