The world equestrian number one Andrew Nicholson says a difficult cross country awaits riders at this weekend's Burghley horse trials in England.
Nicholson is third after the dressage on Nereo, while compatriot and Badminton champion Jock Paget is leading on Clifton Promise.
Nicholson says the the Sir Mark Phillips designed cross country course is undulating and designed to tire the horses.
He says the second section of the course opens up tempting riders to make up time, but their mounts are tired by this stage and prone to errors.
New Zealand's Jonelle Richards is 12th on the Deputy while Sir Mark Todd is 18th equal on Oloa.