Serbia begin their Group D campaign against Ghana in Pretoria on June 13 and Antic acknowledged his players will need to step up their performance if they are to reach their goal of making the last 16.
"I think we can play a lot better than we did against the Cameroonians, especially in midfield," Antic told reporters after seeing his team come from behind twice to win in Belgrade on Satuday.
"We did not keep possession well enough because we wanted to get the ball upfield too quickly and the overall performance has left something to be desired.
"But we had some good moments too, competitive matches should bring the best out of the team and they know they need to raise their game for the real thing."
A lively first half produced a flurry of goals as Serbia came from 1-0 and 2-1 down to lead 4-2 at the interval, with Milos Krasic, Marko Pantelic, Nenad Milijas and captain Dejan Stankovic on target.
Clinical finishing is one thing Antic will be happy with after Serbia lost to New Zealand 1-0 and scraped a goalless draw against Poland in their other two World Cup warm-ups.
But central defender Aleksandar Lukovic made it clear that defensive frailties could cost Serbia dearly when the June 11-July 11 World Cup starts.
"We had lapses in concentration and kept losing our focus at the back and we need to address that problem because there will be no room for sloppy mistakes in South Africa," he said.
"It's always good to win a match but I am far from happy with the overall picture because it's a thin line that divides teams in a major tournament."
Serbia also play three-times winners Germany in Port Elizabeth on June 18 and Australia in Nelspruit on June 24.
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