Germany legend Lothar Matthaus warned against complacency but voiced confidence in his country beating Group E rivals Japan at this year’s World Cup in Qatar. The 61-year-old former great urged Germany to focus on themselves ahead of their opener against the Samurai Blue on Nov. 23 at Khalifa International Stadium. Spain and Costa Rica also await the four-time winners in the group stage. “Germany will win against Japan,” Matthaus recently told reporters at Al Janoub Stadium, one of eight venues for the tournament. “But it’s the World Cup…it has many surprises. You have to work hard for 90 mi…