"He is very well but over 2200m from the backmark I can see him having to really chase because horses on the front line such as Bad To The Bone and Kango could run hard to try and beat him," warns Purdon.
"I think the best-case scenario is us settling back with a horse like South Coast Arden and getting a cart into the race on his back. If that happens we can win."
Self Assured will also be having his first standing start since the New Zealand Cup in November. Although he used to be hit and miss from behind the tapes, Purdon doesn't believe that will be a factor.
He and training partner Hayden Cullen also have Mach Dan and Bettor Twist in the race, with Bettor Twist likely to get a nice run close to the speed but Mach Dan not well off on the 10m handicap line.
Butcher is a rival driver happy to help make Purdon's prediction come true, with Kango off the front line and at his best when able to step and keep running.
"I think this week is his real chance but whether he is good enough to beat Self Assured I am still not sure," says Butcher.
"Our fella has got better all season and is far more hardened to open-class racing now and I think he is closing the gap on the best ones.
"He can pace a half [800m] in 55 seconds and be hard to catch but the problem is the absolute best horses like Self Assured can produce sub-54 second sectionals if they have to and it is hard to beat horses like that.
"So we might be in front but if [Self Assured] gets a fair run in to the race, he might be too fast anyway."
While the Roy Purdon could develop into a game of catch-me-if-you-can, tonight's Group 1 Anzac Cup for the trotters may be decided by the attitude of Herlihy driving Bolt For Brilliance.
The 2200m mobile looks a straight two-horse race between Sundees Son and Bolt For Brilliance with the latter's only realistic winning chance if he can get in front (likely) and then stay in front of Sundees Son (unlikely).
If Bolt For Brilliance leads and gets an easy time he has a shot at winning, but Sundees Son may be good enough to sit parked outside him and still win. With that in mind, Herlihy may decide there is no need to do anything too heroic.
Punting at Alexandra Park
The good thing: Sundees Son (R8, No 3) — Champion trotter who has a lot of ways he can win and not many ways he can lose.
Start crucial: The battle between Simply Sam (R2, No 1) and Take The Miki (7) could come down to whether Sam can stay handy from the ace draw. If he can, he is fast but if he can't Miki is strong and may gain the tactical advantage.
Right race: Mr Chip (R4, No 3) — Has been beaten by two smart maidens lately but has gate speed to lead and this field is not as strong.
Fixed quinella: Self Assured and Kango (R10) — One could lead and the other swoop and that probably suits each of their strengths.
Manners make the multi: Highgrove (R7, No 1) — If you are looking for another multi play Highgrove only has to behave to fit the bill.
