It looks like I skipped over this one. This one is also a JRA commercial reference, but its actually Tamamo Cross's commercial and not Oguri Cap's.

Before Oguri Cap and Tamamo Cross, there was a saying that "Grey Horses" cannot run. In 1988 Tennosho, during the final stretch was a single battle between a grey horse and a grey horse. Everyone else could only battle for 3rd place.