Facing No 9 seed Michael Quintero of Columbia, Bass fell in two sets 6-3 and 7-6 (5).

“I felt good,” said Bass on his final match of the tournament. “The courts were a little slick, but he made me work for everything I got. It was a great experience. I only wish I would have done a little better.”

The wet, red clay courts at Rio’s Marapendi Club were also unkind to Paul and Helgeson.

“The courts were slow,” said Paul following a 7-6 (5), 6-4 loss to sixth-seeded Ivan Miranda of Peru. “But, I had my chances.”

Helgeson too was eliminated by a seeded opponent after dropping a three set match to No. 8 Carlos Salamanca of Columbia, 1-6, 6-0, 6-4.

“They weren’t great conditions, but we both had to deal with it,” said Helgeson. “I was hoping to start the last set like I started the first, but I just didn’t get it done.”

Helgeson and Paul represent the U.S. team’s last hope for a medal when the pair teams up for the doubles competition on Thursday. Helgeson/Paul will meet Paraguay’s eighth-seeded Gustavo Ramirez/Juan Carlos Ramirez in their opening match.

“It has been a great atmosphere,” said Helgeson on the Marapendi venue. “Lots of people have come out and the Rio crowd has been into it. It’s a pretty cool experience.”