Ashevill - Former world number one Serena Williams said she felt on the "right track" despite a crushing loss in her long-awaited comeback to tennis on Sunday playing alongside big sister Venus in a Fed Cup dead rubber.
The duo, who have combined to win 22 doubles titles, were outgunned by the unheralded Dutch pairing of Lesley Kerkhove and Demi Schuurs who were playing in their first ever outing together.
The Williams lost 6-2, 6-3 with 36-year-old Serena appearing particularly slow on her feet and poor in her shot selection after more than a year away from the sport.
But she was determined to put on a brave face after the loss took some of the shine off the Americans' otherwise decisive 3-1 win that booked their place in the next round against France in April.
"It felt really good to be back the court. I've been training and it was just exciting to be out there," she said.
"I honestly feel better than I thought I was gonna feel, I feel like I didn't expect to play you know like that for me. So I feel like that I'm on the right track."
It was Serena's first competitive match since winning her 23rd major at the 2017 Australian Open.
The American star took time away from the sport to give birth to her daughter Alexis Olympia and get married, to Reddit co-founder Alexis Ohanian.
Both were in attendance over the weekend, seated just behind the players' box.
Serena had previously said that her path back had been full of "ups and downs", crediting Venus with helping her regain her rhythm.
On Sunday she was happy with the power behind her shots even if her accuracy wasn't quite where it should be.
"I didn't expect to have that much power on my serves," she said. "Even though they didn't go in, it's just the start, I feel like that's a very good step in the right direction."
And she hinted she needed to juggle the demands of motherhood against her career better.
"I didn't manage my time well," she said. "This is literally my first time travelling with the baby and everything so I'm gonna try to do better."
There had been speculation Serena may drop out of Sunday's doubles match, after she did not turn up for practice in the morning with the three other US players.
But team captain Kathy Rinaldi confirmed her participation after Venus won her singles match against Richel Hogenkamp to seal overall victory for the US.
"Serena's gonna be joining her sister Venus!" she announced, to roars of approval before Williams appeared dressed in a white top, dark blue shorts topped off with a red headband.
The Americans had enjoyed enormous support all weekend from the sold-out 5,200-capacity crowd in the mountainous city of Asheville, North Carolina, famous for its historic architecture, breweries and vibrant art scene.
The dead-rubber was supposed to be the feel-good, icing on the cake, but the Dutch players had other ideas.
"To play the two Williams sisters, it's amazing because we won the match," said Kerkhove, 26.
"We knew it just 30 minutes before the match. We just both gave it our all and we just had nothing to lose."
The Dutch players' ability to soak up the pressure was all the more remarkable given that Schuurs, the younger of the pair, was just six-years-old when Serena won her first major tournament.
Venus' participation meant there was no room for Lauren Davis, the US' fourth player.
The seven-time Grand Slam winner, who enjoyed a renaissance year in 2017, earlier shook off a scratchy start to prevail 7-5, 6-1 in her singles match, ensuring the US could continue their defence of the title.
Ahead of the tie, Serena had refused to be drawn on her Grand Slam hopes for the year.
She had initially targeted last month's Australian Open and a defence of her 2017 title but struggled during an exhibition match against Jelena Ostapenko in Abu Dhabi in December, forcing her to revise her plans.
But she hinted Sunday she could make herself available for selection for the US' next round clash in France in April.
"I think ultimately it's up to Kathy, she has a plenty of players to choose from," she said, referring to team captain Kathy Rinaldi. "So many Americans are doing great, hopefully I'll be able to be an option, I'll be doing better by then," she said.