"It was a long match, a lot of points, a lot of effort, long points," Kenin said. "We fought hard till the end. It's disappointing for me 'cause I had like two match points but couldn't turn things around. But I fought my hardest and I did everything I could." Siniakova wasted a 3-0 lead in the final set and the 19-year-old Kenin, who was playing her second match in her debut Fed Cup tie, fought back.

Kenin, who wasted three break points at 5-5, hit 43 winners but also made 76 unforced errors. Siniakova hit 24 winners.

"It was horrible, the worst (moment)," Siniakova said about the match points she faced. "But it's not the end until the final match point is converted." At 3-0 down in the third set, Kenin needed treatment for what seemed to be a thigh muscle problem. The treatment was then repeated several times.

"It was obviously painful for me and I felt like it was just hard for me to move," Kenin said.

Trailing 3-1, the American wasted five break points in a game that took 19 minutes.

On Saturday, Barbora Strycova rallied for a 6-7 (5), 6-1, 6-4 victory over Kenin to put the Czechs 1-0 ahead and Siniakova doubled the advantage with a 6-3, 7-6 (2) win over Alison Riske.

The U.S. is the most successful country in the international team competition and won its 18th Fed Cup title last year with Rinaldi in her first season as the captain. The U.S. had not previously won the Fed Cup since 2000.

On the way to the final, the Czechs beat Switzerland 3-1 in the first round and Germany 4-1 in the semifinals.

The final was marred by the absence of top players.

Siniakova was the highest ranked at No. 31.

After four of the top five U.S. women in the WTA singles rankings — the Williams sisters, Sloane Stephens and Madison Keys — decided to skip it, three players on the team made their Fed Cup debuts.

The Czechs were weakened, too, missing their two top-10 players. Karolina Pliskova was ruled out due to injuries and Petra Kvitova due to illness.

International Tennis Federation President David Haggerty said in Prague the ITF would like to have more top players in the competition in general.

"One of the concepts is to do something similar to what we've done with the Davis Cup. Nothing is determined (yet)," he said.

Haggerty said the ITF would like to expand the Fed Cup World Group to 16 teams from the current eight because "some of the top players are on the teams that are maybe nine through 16."