PERTH, Australia — 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.

Robredo beat John Isner 6-7 (5), 6-3, 7-6 (4) after Martinez Sanchez gave Spain a 1-0 lead by beating Melanie Oudin 6-4, 6-4. Martinez Sanchez and Robredo then beat the American pair 6-4, 7-5 to complete the victory.

In the singles match, Robredo took a 3-0 lead in the final set tiebreaker but Isner fought back to level it at 4-4 before Robredo won the final three points to clinch the match.

Robredo, who won the 2002 Hopman Cup for Spain with Arantxa Sanchez Vicario, had difficulty dealing with the American's serve. The 6-foot-9 Isner had 16 aces in the match.

"It's really tough," Robredo said. "When the ball bounces high it's really tough to hit."

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.