British star William Fox-Pitt is firmly on course to win his second Rolex Kentucky title in three years.
And the world number one could also capture eventing's coveted Rolex Grand Slam, awarded to any rider who lands consecutive Burghley, Kentucky and Badminton crowns.
Fox-Pitt produced a brilliant cross-country round aboard his 2011 Burghley champion Parklane Hawk.
They were only the third combination to jump clear inside the time among more than 30 pre-lunch starters, which left them on their overnight dressage score of 41.3 penalties.
Fox-Pitt is guaranteed to be first or second going into Sunday's showjumping finale, depending on what overnight leader American Allison Springer does later in the day.
And if he wins in Kentucky, he would then need to triumph at Badminton next week for a Grand Slam and its £220,000 prize, which has only been achieved once before - by Britain's Pippa Funnell nine years ago.
"It is a clever course, very well presented, but it was there to be jumped," Fox-Pitt said. "There were not a lot of options, really, if you were going to be competitive. You just had to get out there and attack it, and we are in a good position."
Reflecting on Parklane's dressage test, Fox-Pitt added: "He is a fantastic horse with great ability and good focus. The test wasn't 100% perfect and showed a few glitches he didn't have last year. He felt the pressure of coming back in a big arena and was a bit edgy at times, but overall, he did a great job.
"This weekend will tell me more about his abilities. If all goes well, he could be the one for Greenwich (London 2012)."
Fox-Pitt's British colleagues Lucy Wiegersma and Oliver Townend were among the later cross-country starters on a course that claimed its share of casualties. There were seven eliminations and six retirements during the day's opening half, with the retirees including California-based British rider James Alliston (Jumbo's Jake) and New Zealander Andrew Nicholson (Calico Joe).