The Rome club defeated Milan 3-2.
"Our ambitions remain the same, because this win changes nothing," insisted Petkovic.
"Scudetto? The fans have every right to think about it, but we must keep our feet on the ground. After all, we saw what happened when we went 3-0 up.
"After conceding the first goal, we just stopped playing. We were also tired, Milan put us under pressure and we conceded some goals that could've been avoided. Nigel De Jong's goal came about because the defensive wall was not positioned correctly.
"In any case, the three points are important for the project that we are taking forward."