Zara Phillips' Olympic debut went according to plan as the London 2012 eventing competition continued at Greenwich Park.
Phillips, watched from the main arena stands by her mother the Princess Royal and grandfather the Duke of Edinburgh, put in a solid display on High Kingdom.
Their score of 46.10 put them into equal ninth position and also kept Great Britain firmly in the team medal mix.
She received a rousing ovation from a bumper crowd before and after her dressage test.
Phillips' previous Olympic hopes in 2004 and 2008 were dashed by injury to her world championship-winning horse Toytown.
"It was incredible to be selected, and to be here at home for the Olympics is an amazing feeling. You try to do your best for the team," she said.
"It was probably his second big test after Burghley last year. His first change was disappointing, but his other ones were really good. But he coped with all the crowd, and he is only getting better. He is very chilled and getting stronger all the time."
Phillips will next be seen in Monday afternoon's cross-country phase, and she added: "He is a good jumper and cross-country is his strongest phase.
"He is quite quick and easy to turn, so it will hopefully be good.
"I think he wants to get out there now. He's a bit bored of dressage!"