The lineup that beat the Germans in Port Elizabeth on Friday were honing their passing skills in a six-a-side game during Saturday's practice, having to score with their weaker foot and do press-ups every time they conceded a goal.
"The ball movement was better than in the opening 1-0 defeat by Ghana but it's still not good enough and there is room for improvement in every department," Jovanovic told Reuters at the end of the training session.
"We sat back in the second half and lost our grip on the game after we scored with an extra man on the pitch. We stopped creating space but fortunately we weren't punished for it.
"It was completely subconscious because we were up against a very good team and the fear of conceding a goal after we had worked so hard to score crept into the team.
"We must not be on the back foot ever again if the opponent is reduced to 10 men because incisive passing is our trademark."
Serbia's win over Germany was their first over a top-ranked soccer nation since the 1990 World Cup, when the former communist Yugoslavia beat Spain 2-1 in the round of 16.
Jovanovic said it gave the Serbians, playing in their first World Cup as an independent nation, a massive confidence boost.
"We are elated and relieved at the same time because it was also our first win against Germany in 37 years and it came after a shocking defeat by Ghana which was difficult to accept.
"We bounced back in the best possible way, this success has given us a new pair of wings and we will head into the match with Australia full of confidence in our abilities.
"Those of us who are lucky take part in one or maybe two World Cups, it's a narrow window of opportunity for most players and we have a huge motive to secure a berth in the last 16."
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