The white gloves come off Saturday as demure dressage gives way to cut-throat cross-country competition at the Rolex Kentucky Three-Day Event.
The top 14 horse and rider pairs are separated by 10 points or less, meaning any mistake on the 6,410-meter course will be costly.
If a rider finishes a second off the optimal time of 11 minutes, 15 seconds, it will cost 0.4 penalty points. That might not sound like much, but it could be enough to drop a rank or two.
An actual mistake, such as refusing a jump, could knock a horse out of the prize money.
Going into the exciting cross-country jumping phase, the leaders after dressage were Allison Springer, an American, with a score of 39.8 on Arthur, her Irish Sport Horse gelding.
She will need wings to stay ahead of the closely bunched pack of world-class riders right behind her.
Springer said she would concentrate Saturday on sticking to her plan and her horse.
"You do get nervous," she said. "I know I can do everything out there. ... Last year I had a tremendous round ... until I was on the dirt."
In second place is Great Britain's William Fox-Pitt, the Burghley champion going for the second leg of the $350,000 Rolex Grand Slam and the current leader in the world standings.
Fox-Pitt, who won Rolex in 2010, was mobbed by young fans after his ride Friday on Parklane Hawk earned him a score of 41.3.
Just behind Fox-Pitt are some hungry Americans: newcomer Clark Montgomery on Loughan Glen with a score of 43.2, and veteran Karen O'Connor on Mr. Medicott with a score of 44.2.
Cross-country can turn on a dime: any slip could open the way for any of the top 15 to come zooming up. Competition is especially intense this year as riders attempt to impress selectors for the Summer Olympics in London.
The cross-country course at the Kentucky Horse Park, designed by Derek di Grazia, won't make it easy: there are multiple water jumps, and several obstacles at maximum heights and spreads.
Fox-Pitt said the course was deceptively smooth.
"There are a few little things out there that will have quite a cumulative effect," he said. "By the time you get to the third-to-the-last, you'll certainly know you've jumped a four-star."