Double Olympic medallist Tom McEwen praised his “phenomenal” Tokyo Games ride Toledo De Kerser after he took early charge of the Badminton Horse Trials.
Gloucestershire-based McEwen helped Great Britain win a first Olympic eventing team gold medal for 49 years last summer, and he also secured individual silver.
McEwen and his Tokyo team-mates Oliver Townend and Laura Collett are among the major British challengers in pursuit of Badminton’s £ 100,000 top prize across four days of dressage, cross-country and showjumping.
Bumper first-day crowds in South Gloucestershire – Saturday’s cross-country is already a confirmed 110,000 sell-out – saw McEwen thrive on an early draw as he posted a dressage score of 23.4 penalties to lead overnight.
“He was phenomenal,” McEwen said. “The half-passes were lovely, he was smooth in his body and kept up a great rhythm.
“It’s lovely to be back here at Badminton, and it was pretty well a mistake-free test.”
Wiltshire riders Kitty King and Mollie Summerland hold second and third spots, with 2021 European team gold medallist King coaxing a score of 24.8 out of Vendredi Biats.
And Summerland, who won the Luhmuhlen five-star event in Germany last summer, marked her Badminton debut by posting 24.9 on Charley Van Ter Heiden.
Another Badminton newcomer – American Tamra Smith – lies fourth with Mai Baum on 25.3, while world number one Townend, riding Swallow Springs, and defending Badminton champion Piggy March share fifth spot.
March and Vanir Kamira won the event when it was last staged three years ago, and she said: “I have been slightly panicking that she (Vanir Kamira) remembers 2019 too well.
“The last time we went in the main arena here I milked it for all I could, doing a lap of honor 20 million times and yelling like a crazy thing!
“We haven’t been anywhere for two years, but she’s pretty professional and I do forget that sometimes.”
Dressage continues on Friday, with Townend (Ballaghmor Class) and Collett (London 52) riding their Olympic horses, before attention switches to the often pivotal cross-country phase and its immense 32-obstacle challenge over more than four miles’ distance.