Tommy Robredo and Maria Jose Martinez Sanchez each won their singles matches before combining in mixed doubles to give Spain a 3-0 win over the United States at the Hopman Cup on Sunday.
Spain and Romania are 1-0 in Group A, while Australia, which lost to Romania 2-1 on Saturday, and the U.S. are 0-1. In Group B matches Monday, Andy Murray will lead Britain against Kazakhstan, while Germany takes on Russia.
The top teams in each group meet in next Saturday's final.