Petkovic's job was on the line going into the game.
"If Lazio had lost today, it would certainly have been a very different debate," he told Sky Sport Italia after a 2-0 victory.
"There is some positivity now, but we're aware of the pressure coming from the outside. We heard the jeers when we started to make some mistakes and felt the pressure psychologically, but I must compliment the lads for keeping calm till the very end.
"I told the players at half-time to enjoy their football and get back to having fun with the sport.
"I had no signs from the club suggesting I would be in trouble if we failed to win. We were relaxed in the second half, believed in what we had to do and in the end achieved it."
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