Poppy Maskill and Tully Kearney both claimed stunning golds as Great Britain won a total of six medals on the opening day at the Paris 2024 Paralympic Games.
Maskill, 19, set a world record to deliver ParalympicsGB's first gold in the French capital, winning the women's 100m butterfly S14 title in one minute 03.00 seconds.
World record holder Kearney then upgraded her Tokyo silver in the women's 200m freestyle S5 to put the British team second in the medal table behind China.
Teenager Will Ellard earlier won men's 100m butterfly S14 silver in the pool, after Daphne Schrager and Steve Bate also clinched silvers in the track cycling.
However, team-mate and four-time Paralympic champion Kadeena Cox was left distraught after she crashed out of her gold medal race at the velodrome.
There was also Para-table tennis bronze for 14-year-old Bly Twomey and team-mate Felicity Pickard in the women's doubles W14 as the British team made a superb start to the 11 days of competition.
Maskill and Kearney starred for ParalympicsGB as the British team made a golden start in the pool on the first evening of Para-swimming action at La Defense Arena.
Maskill shone on her Paralympic debut, delivering her nation's first gold moments after team-mate Ellard had taken silver in the men's race - a feeling she described as "unreal".
The world silver medallist finished ahead of Hong Kong's world champion Yui Lam Chan and Neutral Paralympic athlete Valeriia Shabalina.
"I was just hoping to swim my hardest and see what happens and that's what I did. This gives me so much confidence for my other events," said Maskill.
"Being here at my first Paralympics feels unreal. My mum, dad, sister and nan are here and I can't wait to see them."
In the final event of the night, Kearney made it double gold delight for GB as the 27-year-old held off the challenge of Ukraine's Iryna Poida in the closing stages.
That came three years after Kearney missed out to China's Li Zhang by 0.12 seconds in the event - although she did win gold in the 100m freestyle S5.
"I'm just absolutely ecstatic and a bit speechless. I really wanted redemption from Tokyo," Kearney said.
"To be able 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, or how many events I would be able to do."
Ellard, 18, was the first British Para-swimming medallist with his silver. The European champion led for much of the final but Denmark's Alexander Hillhouse overhauled him for gold, winning by 0.25 seconds.
Debutant Schrager won GB's first medal of the Games in the women's C1-3 3000m individual pursuit, the 23-year-old losing out to Xiaomei Wang of China in the gold medal race despite setting a world record in her C2 classification.
Wang finished nearly 10 seconds ahead of Schrager, world champion at C2 level, and almost lapped her in the process of setting a new C3 world record.
"I'm very privileged to have got a medal at all and to do it in front of my family and friends and the whole team is an amazing achievement," said Schrager, who was presented her medal by cinema legend Jackie Chan on the podium.
GB's Daphne Schrager embraces China's Xiaomei Wang after winning a silver medal
Schrager's success was swiftly followed by another Para-cycling silver, achieved by team-mate Bate and his pilot Chris Latham in the men's B 4000m individual pursuit.
In the final track event, Bate and Latham finished 2.2 seconds behind world record holders Tristan Bangma and Patrick Bos of the Netherlands, who retained their title in a repeat of the Tokyo final.
The 47-year-old Bate, gold medallist in Rio, and Latham smashed the world record in the heats, but that was bettered by the Dutch pair in the next heat - and again in the final.
The velodrome also witnessed heartbreak for one of the team's big gold medal hopes.
Cox's bid for glory was ended by an early fall in the women's C4-5 500m time trial final, won by the Netherlands' Caroline Groot.
The 33-year-old Briton, who endured a turbulent build-up to the Games following a recurrence of her multiple sclerosis which left her unable to walk, and a calf injury, had to be assisted off the track but avoided serious injury.
The first British athlete to win gold medals in two different sports - cycling and athletics - in the same Games at Rio 2016, Cox will now hope to contest the open C1-5 750m team sprint on Sunday.
"It was a weird one. I didn't feel comfortable in the gate. My right side is my weak side and I think I overcompensated," said Cox.
"I got back on the bike two weeks ago. I was in a boot four weeks ago. It has just been a really rubbish year. This time last year I couldn't walk because I had a really bad relapse that affected my right side.
"It has been a rollercoaster, I guess that's MS. It's just not what you want a year out from the Games. The fact that I got here was amazing in itself."
Bly Twomey competed in the women's doubles and mixed doubles on Thursday
Twomey made history as Great Britain's youngest Paralympic table tennis medallist as she took bronze on her Games debut alongside team-mate Pickard, 30.
"It's amazing because I am so young. I wouldn't have done this without Fliss so I am really proud to have her by my side," Twomey said.
"It feels amazing, the atmosphere is just incredible. I'm really proud to get a medal at my first Paralympic Games and I think it means a lot to be doing it at 14."
The British pair recorded a 3-0 win against a Norwegian pair in their quarter-final match to guarantee a medal, but missed out on the gold medal match after losing to China's Wenjuan Huang and Yucheng Jin.
Seven-month pregnant para archer Jodie Grinham competed in the heats of the women's individual compound on day one.
Rio 2016 silver medallist Grinham, 31, is believed to be the first woman that far into pregnancy to have been selected for the British Paralympic team, and hopes she can send out a powerful message to women.
The Briton progressed to the last 16 after setting a personal best score of 693 to place fourth overall, while team-mate and defending champion Phoebe Patterson Pine will hope to join her in the next phase.
"It's brilliant to get that score, I want to compete. I didn't want this Games to just be about a pregnant woman taking part, I wanted to be competitive," Grinham said.
"I'm pregnant, so what? If I worked in an office they'd be fine with me working there until I'm 39 weeks pregnant. What's the difference competing at the Paralympics? I want to be a mother and an athlete. I'm not willing to sacrifice either of them."
Celebrity fans including cinema legend Jackie Chan were present on the opening day at Paris 2024, with Chan watching the Para-taekwondo before handing out medals at the Para-cycling
Former Liverpool manager Jurgen Klopp was in the crowd at the Para-badminton to support friend Wojtek Czyz, who competes for New Zealand
NPA stands for Neutral Paralympic Athletes (NPA) - the delegation representing athletes from banned nations Russia and Belarus