Davenport -- a former world No. 1 -- lost 6-1, 7-5 to Sabine Lisicki, but the Americans drew even when Ashley Harkleroad downed Germany's Tatjana Malek, 6-1, 6-3.
The event is being contested in La Jolla, Calif.
Davenport's shocking loss left her overall Fed Cup singles record at 25-2. It was her first defeat in a Fed Cup match since 1994. She has not appeared on a losing team since 1995.
The United States is 7-4 all-time against Germany and is after its 18th Fed Cup title.
Russia and Israel are 1-1, China leads France 2-0, and Spain has a similar 2-0 lead against Italy after Saturday's other Fed Cup action.