West Midlands teenager Tully Kearney landed her second gold at the IPC Swimming World Championships in Glasgow with a dominant freestyle display.
Kearney, 18, who won S9 100m butterfly gold on Friday, followed up with a new European record in the 400m freestyle.
Fellow teenager Hannah Russell won the S12 50m freestyle by 0.02secs from Russian Darya Stukalova, who pipped her to gold in the 100m backstroke.
"I knew it would be close at the finish but I'm really happy," she said.
"I came into the race thinking I had a chance of a good performance because of my speed but you never know."
Russell's gold completed a superb day for the visually impaired swimmer from Guildford after she took silver in the S13 100m freestyle earlier in the evening, swimming against more sighted rivals.
Team-mate Kearney led from the start of her race and finished in a time of four minutes 39.29 seconds - beating fellow Briton Stephanie Millward's European mark of 4:40.01.
"The 400m free is my favourite event and it's amazing to win another gold," she told BBC Sport afterwards.
Kearney, who has a progressive neurological condition that causes muscle weakness, won bronze in the 400m freestyle at the last Worlds two years ago in the lower-impairment S10 category, but she was reclassified earlier this year and now swims against more disabled athletes than previously.
She was training at Ellie Simmonds's old club at Boldmere but moved to the National Performance Centre in Manchester earlier this year.
"I've been working really hard both at Boldmere and Manchester," she added. "I'd have been happy with a personal best because it is a while since I've got close to that.
"This is the best week of my life and I'm so excited for Sunday's medley relay final."
Ollie Hynd completed the GB haul on the penultimate day of the event with his third medal, taking bronze in the S8 100m backstroke.