The Biancocelesti boss has rued his side's finishing in the 0-0 draw with Apollon, where a win would have all but sealed their progression to the knockout rounds
The Rome outfit registered a total of 27 shots against the Cypriot minnows, but were eventually unable to make the breakthrough.
However, the Bosnian coach feels that his side need to keep working hard and they will eventually register a scoreline that reflects their dominance, and hopefully secure qualification along the way.
“We lacked that little bit of luck, even with the ricochets,” he Sky Sport Italia.
“We need to believe more, be calm and continue working. We believe we can qualify, because we have earned two away draws and a home victory.
“A win over Apollon would have basically closed the group, but we didn’t manage it.”
Lazio currently sit second in Group J, two points behind leaders Trabzonspor. They resume Serie A action by hosting Cagliari on Sunday.