Mexico City proved a challenging site since it was 2,300 meters above sea level, resulting in 30% less oxygen in the air.
Therefore, nations were advised to ship in horses 3–4 weeks before the competition, which would allow them time to recover from the long travel, as well as adjust to the difference in altitude.
France and Germany were the last countries to send their horses, who arrived 28 September 20 days before the competition was to start.
125 entries (including 22 women) from 18 nations competed: Bolivia, Brazil, Canada, Chile, German Democratic Republic (GDR), France, Federal Republic of Germany (FRG), Great Britain, Ireland, Italy, Japan, Mexico, Poland, Soviet Union, Switzerland, and the USA.
Therefore, the horse of second rider Ada Matheson was sent back to the stable, so was not ready when she was called, eliminating her from the competition.
However, Kizimov rode a great test for 664 points, compared to Neckermann's 598, allowing him to pull ahead for the individual gold medal.
In addition to the trouble caused by that fence, there were two equine fatalities which occurred before the rain: the USSR's Ballerina and the Irish eventer Loughlin.
This allowed Guyon to move up to the gold medal spot, followed by British rider Derek Allhusen on Lochinvar and American Michael Page on Foster.