Ajax of course remembered for his defeat in the Rawson Stakes in 1939 at 1/40, as much as his 18 straight wins.
If I remember correctly, it was a pretty blustery day, and a few took the £1000 to win less than £30 on Ajax. With only 3 running, it was a dawdling pace, and Spear Chief came from "the back" of the field.
I always put his defeat down to a horse that had been racing "the other way" down in Melbourne, where he had been and raced for about a year. For a long-striding horse, Ajax had to overcome not only racing in the opposite direction, but a tight-turning track as well.
They sent him up to Sydney by rail about a week prior I think. It would have been an easier proposition if he was set for Randwick for a first-up Sydney run.
They said the Rawson would be something of a training run for Ajax, and the next day the headlines were "Ajax beaten". Spear Chief started at 33/1, he was a moderate performer, and was not given a realistic chance of winning.