After an outdated stanza of the German national anthem was sung during the opening ceremonies, the United States took a 1-0 lead and was ahead in the other opening match in its best-of-5 Fed Cup quarterfinal Saturday. Alison Riske beat Andrea Petkovic 7-6 , 6-2, and CoCo Vandeweghe led Julia Goerges 6-3, 3-1 when rain halted play.