Serena Williams suffers extraordinary 21-year first in Fed Cup loss

Serena Williams has lost the first Fed Cup singles match of her career, falling to Anastasija Sevastova and forcing the United States to claim the best-of-five series over Latvia 3-2 with a doubles win.

Sevastova won the Saturday night rubber 7-6 (7-5) 3-6 7-6 (7-4), avenging a loss to Williams in their only previous meeting in the 2018 US Open semifinals.

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This time it was Sevastova celebrating, closing out the match with a huge serve Williams couldn't return.

Williams had been 14-0 in Fed Cup singles dating to her debut in 1999, including a straight-sets win over Jelena Ostapenko on Friday night that had two tiebreakers.

"It's obviously hard to play Serena and she's an amazing champion," Sevastova said.

Serena Williams reacts while competing against Anastasija Sevastova. (Photo by Abbie Parr/Getty Images)

"You just try and enjoy it as best you can and give your best."

The US now advances to the Fed Cup Finals in April in Budapest thanks to Australian Open champion Sofia Kenin and Bethanie Mattek-Sands who teamed up for a 6-4 6-0 victory over Ostapekno and Sevastova.

Kenin had taken the place of Alison Riske to play her third match in barely 24 hours.

While she may have looked fatigued in her three-set loss to Ostapenko earlier in the day, she found a boost teaming with the energetic Mattek-Sands.

Doubles deciding the Washington meeting was a surprise after both Kenin and Williams won on opening night. Even after Kenin lost Saturday's opener, there was still Williams' imposing Fed Cup record to carry the day.

Serena Williams suffered the first singles loss of her Fed Cup career. (Photo by Abbie Parr/Getty Images)

USA still advance to finals

She did have chances to clinch a victory for the US and wrap up their spot.

She rallied from a 5-2 deficit in the opening set by winning four straight games and then had three set points with Sevastova serving.

However the Latvian managed to hold serve thanks to a couple of errors by Williams and a pair of aces.

Williams broke the serve of Sevastova four times in the second-set but couldn't find the same success in the final set as both players held serve into the tiebreaker.

She pulled even at 4-all but Sevastova won the final three points.

Ostapenko beat Kenin 6-3 2-6 6-2, breaking her four times in the third set.