Britain's double Olympic champion Charlotte Dujardin broke her second world record at Olympia 2014 as she secured freestyle victory with Valegro.
The pair, who set the previous freestyle dressage record of 93.975% at last year's event, bettered that total with a stunning 94.3%.
It followed their world record in the Grand Prix discipline on Tuesday.
"It was definitely the ride of our lives. Valegro is just an incredible horse," Dujardin told BBC Sport.
"He's just a true horse of a lifetime. It feels incredible to come here year after year and keep breaking world records."
Freestyle dressage sees a rider and their horse perform routines to music, whereas the Grand Prix sees them attempt a set list of moves.
Edward Gal of the Netherlands (83.550%) was second, riding Globck's Undercover N.O.P, whilst Germany's Jessica Von Bredow-Werndl (80.723%) was third with Unee BB.
Valegro's owner Carl Hester, riding Nip Tuck, came fifth and believes Dujardin and her ride can continue to push the boundaries of the sport.
"He's a complete phenomenon as a horse," Hester told BBC Sport.
"I'm pleased with how Nip Tuck is progressing, though, and if the 2016 Rio Olympics were tomorrow he would be going, so it's looking good.
"With another 18 months until the Games, I think we can all still make improvements."
The year-ending Olympia event, officially known as the London International Horse Show, runs until Monday.