Katie Boulter claimed a dominant win to pull Great Britain level against Sweden in their Billie Jean King Cup play-off after Jodie Burrage lost on her debut.
A nervous Burrage, ranked 279 places above opponent Kajsa Rinaldo Persson, let slip a 4-0 lead to lose 6-4 6-1.
However, British number one Boulter got Britain back on track with a 6-2 6-1 win against Caijsa Hennemann at London's Copper Box Arena.
The British pair will be back in action in the best-of-five series on Sunday.
Great Britain, ranked 14 places higher than Sweden, had gone into the tie as the overwhelming favourites, with all of Sweden's players ranked outside the world's top 350, but the play-off is proving tighter than it had looked on paper.
'A lot closer than the scoreline'
Having been on the sidelines to watch Burrage's opening defeat, Boulter came on to the court with an added level of pressure.
However, the 27-year-old did not appear to feel it - breaking her opponent at the first opportunity.
While Boulter's serve was threatened on occasion, the Briton held firm as Hennemann missed five break points in the opening set.
The world number 58 continued to grow in confidence and, using the sell-out crowd's support as motivation, she raced through the second set to wrap up an assured victory in one hour 17 minutes.
"These [Swedish] girls are playing way above the level, they're all having a swing, they're having a go at people who are ranked higher," Boulter said.
"I expected an absolute battle out there today. It was definitely a lot closer than the scoreline.
"They've got nothing to lose and they're going to come at us with their best tennis so we have to be ready."
'I haven't felt nerves like this'
Making her debut in the women's team event, Burrage started brightly before nerves took hold and Rinaldo Persson went on an eight-game winning streak and took 11 of the final 12 games.
"I have not felt like this and even the nerves before have not felt like this. Ever," Burrage told a news conference.
"I'm very disappointed that I didn't get everyone a win.
"It's not just me out there. I'm playing for other people and that type of pressure I have never really understood before and I don't think you ever do until you do it.
"That's why it hurts even more, because I'm hurting for other people."
Rinaldo Persson looked unstoppable when she claimed the first two games of the second set, and despite eventually holding to get herself back on the scoreboard, Burrage - who was cheered on by a partisan crowd - never threatened a comeback.
Speaking after her victory, Rinaldo Persson said: "This is one of the biggest wins of my career.
"It wasn't that great of a start for me, but right now I am super happy I got the win."
Will GB stick with Burrage on Sunday?
While Boulter will undoubtedly be in action on Sunday, taking on Rinaldo Persson in the day's first singles match, there are questions over whether captain Anne Keothavong will stick with Burrage after her surprise defeat.
The British number two said she would respect Keothavong if she decides to swap her out for the match against Hennemann and bring in Harriet Dart or Heather Watson.
"That's going to be her decision at the end of the day," Burrage said.
"If she picks me, I will give my absolute all like I did today. I gave everything I could today. I just wasn't good enough."
Speaking after Saturday's action, Keothavong said it was a decision she would discuss with her team, but that she felt disappointed for Burrage "given that was her debut in this competition and you want it to be a positive experience".
"It's going to be a tough one for her to take, but she's got to find a way to bounce back if she's going to keep putting herself in positions for selection," Keothavong said.
"For that to happen in front of a home crowd, it's a tough one for her to take but she will bounce back and she will learn from this."
If the play-off has not been settled after the fourth singles rubber on Sunday, Dart and Watson will take to the court in a deciding doubles match against Lisa Zaar and Bella Bergkvist Larsson.
Keothavong's squad will be demoted to the Group I stage of the competition - the level below the top world tier and played regionally in the European/African zone - if they lose the best-of-five series.
Sweden - four-time quarter-finalists - are vying for promotion to the top tier of the team event having played in the European/African zone since 2016.
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