Great Britain's Natasha Baker laid down an emphatic equestrian gold medal marker at Greenwich Park on Saturday.
The Paralympic Games debutant took a clear lead aboard Cabral in the Grade II individual championship.
Their score of 76.857% - a Paralympic Grade II record - put them way ahead of closest challenger, Italian Silvia Verati, but Baker's early draw meant she faced more than a two-hour wait before discovering her fate.
Her main rival, Germany's Britta Napel, is drawn near the end of a 23-rider competition and is defending the Paralympic title she won four years ago.
Triple 2011 European gold medallist Baker underlined the strength of her partnership with Cabral as Britain's five-strong dressage team awaits its first medal in London.
"We kind of stepped it up a gear today - he just felt amazing," Baker told Press Association Sport.
"His warm-up was the best he has ever done. He is such a responsive horse.
"He really listens to me, especially under pressure. Considering I have got no use of my legs, he really does have to try hard. He is a super horse.
"I am going to and say hi to my family now, but I am not sure if I can watch the other riders.
"I might have no finger nails left by the end of it."