Carl Hester says he and his horse Nip Tuck are capable of doing well at next summer's Olympics in Rio.
The 2012 team dressage gold medallist won the freestyle dressage title at the London International Horse Show.
"Last year I competed there and came fifth and it was quite a difficult ride, but it was totally different this year," Hester told BBC Radio Guernsey.
"It's fairly unbelievable that he's come this far and he looks like an Olympic prospect."
Hester beat Olympic individual dressage gold medallist and stable mate Charlotte Dujardin to the title at Olympia, and says the pair are hoping they will be selected for the 2016 Olympics.
"He (Nip Tuck) was fifth at the European Championships this year and we won the team silver, so we're definitely in the running for Rio," added Hester.
"So far Charlotte and I are in the top 10 at the moment in the world rankings.
"But with horses you have to be aware that they have to fit on the day, they have to have no problems and be fully up to the job, because it's a very big ask - flying horses to Rio and then the competition ahead of them."