Arsenal manager Arsene Wenger believes Australia can upset Germany in their Group D opener on Sunday.Wenger believes the Germany camp is losing sleep over the prospect of meeting the Socceroos in DurbanThe Frenchman claims Australia are a major threat to the three-time champions' hopes of topping one of the toughest groups at the tournament, sensing Germany may be caught off guard."If I was national team coach of Germany and I had to play Australia first, I wouldn't sleep well," Wenger said on Thursday."It will be interesting. Australia are tough cookies in the World Cup (and) sometimes Germany are slow starters in the big competitions."Maybe Australia can take advantage of that. I give them a chance against Germany."I wish they do (beat them) because it will make it a very interesting group."Wenger gives Australia a 40 percent chance of knocking out Germany and shaking up the predicted pecking order in Group D.But Germany coach Joachim Loew doesn't appear to be losing sleep over the up-coming contest, instead hinting fans will be the ones dozing off due to the Socceroos' defence-orientated game."Australia can be expected to offer anything but a great spectacle,'' Loew said."Australia is all about top organisation, incredible work-rate and almost a perfect defence."It's very difficult to unbalance that team."Many other nations have had a very hard time against Australia."Germany great Franz Beckenbauer cautioned his countrymen against taking Pim Verbeek's men lightly, using Australia's 1-0 loss to Italy at the 2006 World Cup to illustrate his point.Beckenbauer warned: "Don't under-estimate Australia.'"We all remember Australia gave Italy a very hard time."Source: Soccerway.com