"We have enough quality and depth in the squad to carve out three much-needed points and we are not paying attention to suggestions that this is the worst situation we have been in," Bilic told a news conference on Wednesday.
"I don't have too many doubts about my starting lineup but we are yet to decide whether to deploy the standard 4-4-2 formation or a more attacking 4-4-3," he said.
Defeat or even a draw would leave Croatia's bid to qualify for next year's finals hanging in the balance and daily Jutarnji List suggested their position is precarious.
"Bilic's position only seems to be relatively comfortable but in reality, his team is in trouble if Ukraine comes away with anything from Zagreb," it said.
"The fixture list favours the Ukrainians because they play Andorra twice and will be at home to England, while we have to go to Wembley in our final match."
"Petric is showing signs of his best form in a while, and I have made it clear to him and other forwards we expect them to fire on all cylinders on Saturday.
"I am sure they will rise to the occasion and it's also a good thing that players battling niggling injuries look like they will be fit."
Bilic's counterpart Olexiy Mikhaylichenko is likely to leave his unsettled striker Andriy Shevchenko on the bench for what he sees as an "important but not decisive" match and hinted his side would play cautiously.
"Our priority is not to lose and show our potential in attack when the opportunity comes, because we have a game in hand and everything is open," he said.
