Germany face the threat of elimination if they fail to beat Ghana in their crunch Group D clash in Johannesburg.
After a thumping opening win over Australia, Joachim Low's men went into their last game against Serbia in a confident mood.
But things did not go according to plan and, following a red card to striker Miroslav Klose, Serbia went on to win 1-0 as Lukas Podolski missed from the penalty spot.
It means that Germany must beat the Black Stars at Soccer City to progress, as a draw will only be enough if Serbia fail to win against Australia.
All four teams in the group can still qualify for the knockout rounds and Ghana currently top the pile having picked up four points.
They beat Serbia 1-0 in their opening match, and were held to a 1-1 draw against the Socceroos on Saturday.
With African sides not faring too well this summer, the whole continent will be behind the Black Stars to advance.
One interesting side-issue in the game will be the presence of Ghana midfielder Kevin-Prince Boateng, whose tackle in the FA Cup final on Michael Ballack ruled the Germany captain out of the World Cup.
Germany insist they will not target the Portsmouth man, but with his half-brother Jerome in the opposition squad, this one could be a fiery affair.
With Miroslav Klose suspended for the game, manager Low must decide who will start up front.
Brazilian-born Cacau could play as a lone striker with Podolski, Mesut Ozil and Thomas Muller in attacking midfield.
Apart from that change, Low may not make any other modifications to his young team, five of whom have already been booked and who know another yellow card would see them miss the next match if they progress.
Ghana's Serbian coach Milovan Rajevac is expected to be boosted by the return of captain John Mensah in central defence, while his partner Isaac Vorsah could also return. Both missed the game with Australia through injury.
Rajevac may opt to alter his system and help lone striker Asamoah Gyan by using a second striker or putting Sulley Muntari in midfield.
Muntari has been reprimanded by the Ghana FA after an argument with the manager after the last game, but contrary to reports, he has not been sent home.