Delio Rossi's first appointment as Sampdoria manager is a home tie against the club he spent four seasons with, booking a third-place finish and the Coppa Italia before moving to Palermo.
Lazio can capitalise on any potential slip-up from Inter Milan against Genoa to take second place going into the winter break, but Petkovic is wary of his counterpart's determination to make a good impression at the Marassi.
He told La Repubblica: "He's lived and worked here and I'm sure he's done detailed analysis of our matches.
"He will know us very well indeed.
"We can't allow ourselves to be surprised. They will play a highly aggressive brand of football but a defensively-orientated one.
"He's a coach who knows good football and his teams are always well-balanced and pro-active.
"It's difficult to change a lot inside seven days but I'm sure he will give a quality Sampdoria side a big helping hand.
"Every player will want to prove themselves to the new boss.
"We have to give 120 per cent tomorrow and the concentration levels must increase."
Ederson and Tommaso Rocchi remain injury doubts while Antonio Candreva sits out the trip to the Ligurian through suspension.
Samp, meanwhile, have concerns over forwards Maxi Lopez, Enzo Maresca and Mauro Icardi, with Fernando Tissone serving a one-match ban.
Rossi promised there would be no repeat of the events that saw him dismissed from Fiorentina in ignominious fashion this summer.
The 52-year-old was sacked for attempting to punch midfielder Adem Ljajic, who had sarcastically applauded his own substitution.
"It was a gesture that seemed more serious than it probably was," Rossi said.
"I apologised for it, but my time there was over from that moment. I still have good memories of Florence.
"I hold this club in very high esteem and I hope to rise to the occasion."
Samp have won this fixture three times in a row, offering Lazio just one season's respite during the Blucerchiati's recent stint in Serie B.