"He is still our top pacer and the one to beat in races like this, especially back to equal marks," says Purdon.
Being back on the front line the standing start will be crucial for Spankem because if he can step cleanly and get handy he probably has the respect to surge to the lead, from where he has been near unbeatable.
But if he gets back in the field on a track where open class pacers routinely peel off 54 second last 800m sectionals, favourite punters will be feeling sick.
While most of Spankem's rivals today have proven open class form, Self Assured is only having his second start in the big time and if he was to win it would cause a re-shaping of the markets for the Inter Dominions and possibly even a change of heart about a New Zealand Cup start.
"At this stage, even if he wins on Monday, we won't be paying the late entry for the Cup," says Purdon.
"But if he won well and Jean (Feiss, owner) wanted to consider it then we might rethink that. I think be will need to begin quickly though. If he is even a touch slow in this field he could settle closer to last than first."
While the open class pacers face their most telling test of the season so far today, the Flying Mile Trot could be a far simpler equation.
If Sundees Son is back to his best he is the one to beat, if he is not then Marcoola probably wins.
Sundees Son had been stunning in his last six starts before a galloping last time out and driver John Dunn has not been entirely happy with how the little fella has been trotting.
If he is below par today then from the ace draw Marcoola has plenty of options to defend the title he won last season.