Britain's Natasha Baker defended her Individual Championship Test Grade III para-dressage Paralympic title at the Olympic Equestrian Centre as compatriot Sophie Christiansen bagged a sixth gold medal.
The double success means that Britain have also reclaimed their team title at Rio 2016.
A fine display on Cabral saw Baker, also the Individual Freestyle Test Grade II champion at London 2012, clinch a third gold of her career with a score of 73.400 per cent.
Dutch combinations secured silver and bronze with Demi Vermeulen second on Burberry with 71.600 per cent and Rixt van der Horst third with 70.743 per cent riding Caraat.
"I am an emotional wreck, I'm still in complete shock," said Baker.
"I can't stop crying, I am just so proud.
"For once, I'm speechless - and that never happens.
"I just cannot believe what happened to me.
"London was so, so special to win it on home turf, but to retain that title, I can't believe it."
Baker managed to win gold despite Cabral not initially feeling at home in Rio.
"A couple of days ago in my first competition, he had a massive spook before we went into the arena and he was just tense and nervous so I didn't reach my full potential then," she said.
"Going into today that was going into the back of my mind and I wanted to be relaxed and calm.
"I just love him.
"He just means the absolute world to me.
"I just said to him when we were trotting around in the 10 minute spot 'trust me, completely trust me,' and he did.
"He just worked with me.
"He felt so relaxed, I'm just over the moon with him.
"This will be his last Championship and I just wanted to show the world what he can do and he allowed me to do that today."
In the second final of the day, Christiansen retained the Individual Championship Test Grade IA title she won in London as she struck gold for a sixth time.
She scored 78.217 per cent to win on Athene Lindebjerg with another Briton, 67-year-old Anne Dunham, clinching silver on LJT Lucas Normark with a tally of 74.348.
Dunham has won five gold medals in her career, with the bronze today going to hosts Brazil thanks to Sergio Oliva's 73.826 on Coco Chanel.