By ESPNSTAR.com staff
Lazio are currently third in the Serie A table after a strong start where they won five out of their first seven games - an excellent start to Petkovic's Lazio career after taking over from former manager Edy Reja in the summer.
However, the Bosnian has told his players that they will have to keep their heads down and continue working hard despite their strong position.
He told Lazio Style Radio: "We have to keep our feet on the ground. We have done well, but are also aware we are not 100 per cent. We always want to keep control of the game, which isn't easy, but so far, the players have worked hard and shown some pretty positive things.
"We worked very well in pre-season, but the turning point was the last friendly with Malmo and our first victory in an official game, as that is when we started to believe in what we had done over the previous few months."
Petkovic also dropped striker Mauro Zarate for the 3-0 win over Pescara last weekend, a decision he hopes will spur the out-of-form striker to fight for his spot.
"He [Zarate] too has to earn his place in the team, just like all the others," he added.
"I am certain after this break for international duty, those who return will want to give their all to confirm their place or take it off someone else."