Joachim Low's side opened their World Cup campaign with a 4-0 win against Portugal on June 16, before following it up with a 2-2 draw against Ghana last Saturday.
Ozil started both games for his national team but was on the periphery in each, and former German international midfielder Ballack has called for the Gunners playmaker to step up to the plate.
German paper Express quotes Ballack as saying: "I am surprised by the critical views on Mesut Ozil. For me, he is and he remains an extraordinary player.
"Yes, he has not had a overwhelmingly good match at the World Cup until now but he did not disappoint me either. He needs a magic moment, he must force this moment to happen.
"In these situations, Low must back him. Other nations envy us for having players like him or Mario Gotze. They can make the difference."
Germany conclude their group phase against the USA on Thursday and know a point will guarantee their place in the last 16 of the World Cup.
A draw for both teams in the final group game in Recife would see them through, although a defeat for either side could see Ghana or Portugal jump into the qualification spots.
However, in the case of the Portuguese, they would need a large swing in goal difference following their heavy defeat to Germany in their first match.
Ozil has come in for criticism over the last few months, after his performances at Arsenal dipped after a bright start following his club-record £42.5 million switch from Real Madrid at the end of last summer's transfer window.