Sergio Floccari's controversial goal helped Lazio defend its runnerup standing in Serie A.
Coach Vladimir Petkovic praised Lazio's resilience in their 2-0 win over Atalanta, but said their first half left a lot to be desired.
Sergio Floccari on Sunday opened the scoring in controversial fashion after 67 minutes, the Lazio man appearing to handle the ball in the build-up
An own goal from Atalanta's Davide Brivio sealed the win for the hosts.
"Our players didn't make enough sacrifices in the first half of the match, whereas in the second half they performed better and concentrated more," Petkovic said.
There was some debate regarding Lazio's first goal, as Floccari appeared to bundle the ball over the line with his arm.
However, Petkovic has jumped to the defence of the 31-year-old, insisting it was not his intention to cheat.
"I don't believe the referee has given us a gift. The referee could or couldn't have taken that decision," he said.
"I've watched the goal several times and the offence definitely wasn't made on purpose, therefore only the referee could decide whether to give the goal or not."
Petkovic's aim is now to stay second in the standings and continue their nine-game unbeaten run.
"If we keep on producing performances like the one in second half of the match, we can aim at doing well in this championship. If we manage to improve even more, we can aim at holding our position in the table," Petkovic said.