Elizabeth Hudson
BBC Sport journalist in Paris
Teenage swimmer Poppy Maskill created history with Britain's first gold of the Paris 2024 Paralympics.
The 19-year-old from Cheshire, who is making her Games debut, set a new world record to win the women's S14 100m butterfly, describing it as 'unreal'.
Later, team-mate Tully Kearney claimed victory in the S5 200m freestyle - a win she said was 'redemption' for silver in Tokyo.
William Ellard also took silver in the S14 men's 100m butterfly as GB enjoyed a successful opening night in the pool.
Maskill was fastest in Thursday morning's heats and again set the pace in the final, turning half a second clear and finishing strongly in one minute 3.00 seconds, 0.33 clear of the mark jointly held by her team-mate Olivia Newman-Baronius and Russian athlete Valeriia Shabalina, who is representing the Neutral Paralympic Athletic team in Paris.
Hong Kong's Yui Lam Chan was second in 1:03.70 with Shabalina third (1:04.4) and Newman-Baronius out of the medals in fourth (1:04.59).
"It's unreal and it feels weird to be the team's first gold medallist," said Maskill, who was second to Chan at last year's World Championships in Manchester.
"I just wanted to swim my hardest and see what happens. I’ve worked hard in training and listened to what everyone tells me to do.
"It gives me more confidence for my other events."
Maskill is also a strong backstroke swimmer and will aim for gold in her 100m event on Friday, 6 September.
Kearney thrilled with freestyle gold
Kearney, who won 100m gold and 200m silver in Tokyo has had a torrid time since dealing with concussion, a change in racing category - a decision which was later overturned - and mental health issues.
She qualified fastest and although Ukraine's Iryna Poida pushed her hard in the final, the 27-year-old from the West Midlands came through strongly to win in 2:46.50 ahead of Poida's 2:47.16.
"I really wanted redemption for Tokyo," said Kearney. "I was never happy with that silver so to go and get gold is incredible and I am really happy with it.
"It has been really hard with the concussion and then over the last three or four months dealing with my mental health, so to get here means a lot to me.
"Even a few weeks ago, we weren't sure if I was going to come out and compete and how many events I could do, so I am grateful to the team for all the support they have given me."
Ellard happy with silver
Maskill's success came moments after Ellard took silver in the men's race.
The 18-year-old from Suffolk led at halfway with Alexander Hillhouse down in fourth, but the 20-year-old Dane came through in the second part of the race in a new Paralympic record of 54.61 seconds, with the Briton clocking 54.86.
"I didn't think I would be happy with silver but I am," said Ellard. "It gives me more confidence for my 200m freestyle, which is my main event."
Ellard was being interviewed by the media as Maskill won her gold and he was thrilled to see his team-mate achieve glory.
"It's big for the team and a huge personal best for Poppy as well," he added.
"I know she wants to try to get the world record in the 100m backstroke later in the programme, but this is a big bonus for her."
Didier delights French crowd
Earlier, the La Defense Arena reached fever pitch for the opening race of the night as Frenchman Ugo Didier overhauled Italian rival Simone Barlaam to win gold in the men’s S9 400m freestyle.
Didier, 22, had finished second to Australian William Martin in Tokyo and has regularly gone up against Barlaam in their category, with the Italian usually getting the upper hand.
It looked like a similar story again with Barlaam leading most of the race, but Didier made his way through gradually and seized the lead in the final 50m, cheered on loudly by his home crowd.
"It was unbelievable, the cheering for me helped me a lot," he said. "I don't think I could have done it without the crowd.
"I am very happy for this medal but what it means to me is the emotions and to share with all my family and friends."