Ireland sit in 13th place in the team event in dressage after reaching a score 110.40 ahead of the cross-country stage tomorrow.
Sarah Ennis & Horseware Woodcourt Garrison (ISH) scored 38.10 which ranked 50th overall individually.
That's just behind Austin O’Connor and Colorado Blue on 38.00. Sam Watson is 38th after his score of 34.30.
Thailand and Italy are the only teams behind Ireland in the team event. Great Britain lead the overall standings.
"Being honest, I am very disappointed," stated Ennis. "We really thought we had him in a position to get a much better mark.
"He has been going amazing all week. He just got nervous when he went into the ring. We just have to hope that the rest of it goes a bit better."
Under three minutes, the test is half the time of a normal eventing dressage test, which means a lot more movements are packed in. The format asks a lot of the horses and creates plenty of opportunities for the athletes to make mistakes.
The action tomorrow moves from the Equestrian Park out to the Sea Forest Cross Country course, based about one hour from the main venue.
Similarly, to the rest of the Irish team, Ennis is looking forward to the next two phases and knows that it will not only be a dressage competition.
"The time is going to be really influential. It is like an ERM [Event Riders Masters], it is going to be really fast and quick, and I think there are going to be a lot of time penalties out there."
Germany's Michael Jung laid a solid foundation to defend his individual eventing gold medals from Rio and London, beating world number one Oliver Townend of Britain to an early lead.
Jung, who turned 39 on Saturday, was greeted by German journalists singing "Happy Birthday to you, dear Michi" after giving his new horse Chipmunk its first Olympic outing, and said he might have a glass of champagne if his coach allows it.
China's Alex Hua Tian came third individually, with Britain headed for team gold, Germany silver and New Zealand bronze at the Baji Koen Equestrian Park, also the venue for the equestrian events the last time the Olympics took place in Tokyo in 1964.
If Japan, currently in fourth position, end up on the podium, it would be their first equestrian medal since 1932.
New Zealand is represented by husband-and-wife team Tim and Jonelle Price, ranked second and seventh in the world, alongside Jesse Campbell.
Australia's Andrew Hoy could set a record at age 62 by claiming gold 29 years after he first led the pack at the Barcelona Olympics in 1992. He is currently 13th.
