The Germans turned in arguably the most impressive performance of the opening round of games to date on Sunday when they trounced the 10-man Socceroos 4-0 in Durban.
But Stuttgart's Khedira, who proved a more than able deputy for the injured Michael Ballack, knows they cannot afford to allow their standards slip as they prepare for Friday's match at the Nelson Mandela Bay Stadium in Port Elizabeth. Serbia lost 1-0 to Ghana in Pretoria at the weekend and cannot afford another defeat if they are to progress.
Khedira told the German Football Association's official website, www.dfb.de: "We have to be highly concentrated going into the game. We need to take the momentum from the game against Australia into this match.
"But it will not be easy because the Serbs have to win - for them, it is already a final, and they have a lot of good individual players.
"We are focused on the tournament. We had a good start and we also know that we must continue working hard. We want the second victory and to continue to play winning football. We can always improve things."