Goals from Carli Lloyd and Alex Morgan saw the United States beat New Zealand, while Germany was far too strong for Zimbabwe.
The United States kicked off its Olympic women's football tournament with a win over New Zealand, while Germany put six goals past a hapless Zimbabwe side.
The U.S., winner of gold in London in 2012, started things brightly against New Zealand on Wednesday with a goal inside nine minutes through captain Carli Lloyd.
It took the U.S. just seconds after halftime to double its lead, with Alex Morgan finding the net to wrap up a 2-0 win in Belo Horizonte.