Teenager Amy Marren has claimed gold in the SM9 200m individual medley at the IPC Swimming World Championships in Montreal.
Marren, who turned 15 on Wednesday, beat team-mates Stephanie Millward and Claire Cashmore to win with a time of two minutes 33.95 seconds.
The swimmer was disqualified in the heats but reinstated after an appeal.
She made her GB debut at last year's London Paralympics, reaching the 400m freestyle and 100m backstroke finals.
Despite missing out on a medal on that occasion, she came to the fore this year when she set a new European medley record.
But her dream of a world title was in doubt when she was disqualified from the heats after she was deemed not to have moved her arms in the same plane on the breaststroke leg, before a successful appeal.
After finishing six seconds clear of Millward in the final, she told BBC Sport she had to put aside the dramas of the morning session to race again.
"I just channelled my emotions into wanting me to do well in the final. I'm lucky to have the support team behind me that got me back in the race and I'm thankful to them and my coach," she said.
"It's overwhelming to win your first world championships title and I've worked so hard over the past year.
"I've pushed myself in training to the point where my body couldn't take any more and in the last length I gave it my all but I can honestly say it is worth it and is the best birthday present possible."
Elsewhere, there was a medley gold for GB's Ollie Hynd as he set a new European record to win in the SM8 category.
Hynd held off the challenge of Russian Konstantin Lisenkov, adding the world title to his Paralympic and European crowns, but elder brother Sam was fourth, just 0.04sec out of the medals.
"It feels amazing. It's a dream come through to stand on the podium and hear the anthem," said Ollie, who will again go up against his brother in Wednesday's 400m freestyle.
"The race was good but painful over the last 50 metres but I just put my head down."
Squad newcomer Stephanie Slater, who was a talented able-bodied swimmer before suffering a muscle problem which left her without the use of her left arm, marked her first GB appearance with silver behind American Jessica Long, who was winning her 16th world title.
A thrilled Slater beat her personal best by 10 seconds after only returning to the water eight months ago.
"It's so emotional and it means so much to me," she told BBC Sport.
"I've knocked so much off my PB and racing Jesssica Long makes me want to fight even more. I'm so happy. It makes it all the better to have gone through two years of pain to come here and swim like that. It's amazing."
There was also a second silver in consecutive days for Hannah Russell in the S12 100m butterfly while Rob Welbourn was second in the S10 400m freestyle.
Sascha Kindred landed his 15th World medal with a season's best to win bronze in the SB7 100m breaststroke, meaning the 35-year old has won a medal at all six stagings of the IPC World Championships.
Charlotte Henshaw won bronze in the SB6 100m breaststroke ahead of Ellie Simmonds while there was also a first global medal for Tully Kearney who won bronze in the S10 freestyle.