BERLIN (AFP) - German Andrea Petkovic's victory over Melanie Oudin of the United States on Sunday saw the 17-time winners drop out of the top flight for the first time in the competition's 48 year history. The 23-year-old Petkovic needed just one hour 18 minutes to beat 19-year-old Oudin 6-2, 6-3, having already beaten teenager Christina McHale 6-3, 6-4 on Saturday, to give Germany an unassailable 3-0 lead. The USA have reached the Fed Cup final for the last two years but came to Stuttgart with an inexperienced squad. The Americans were missing their three leading players, including both the Williams sisters -- Serena and Venus Williams -- as well as Bethanie Mattek-Sands, ranked 41st in the world. Victory over Oudin extended Petkovic's current Fed Cup singles winning streak to six matches, having won both singles in Germanys 4-1 World Group II victory over Slovenia in February. Petkovic, who reached the last eight of January's Australian Open, is on a career-high ranking of 19 in the world and had few problems against Oudin, who rarely threatened the German number one.