McDonald knows he's on the right type of horse for what is almost certain to be a tough staying test. Tasmanian The Cleaner is a certain leader and with a touch less class than some of the runners, his only chance is to try to run the field breathless with a fast pace.
Nothing will suit Criterion more. "He's a Guineas winner and a Derby winner, so we know he'll keep going in any sort of staying test," says McDonald.
The New Zealand jockey rode Criterion for the first time in trackwork on Tuesday morning and was impressed, describing Criterion as an "uncomplicated horse".
At $6.50 Criterion looks at useful odds behind the favourite Fawkner at $4.40 given he was fast closing on Fawkner in second place in the best form reference to today's big race, the Caulfield Stakes.
David Payne is adamant Criterion is a fitter horse for that run.
The Cox Plate will be a reverse of what we saw in last week's Caulfield Cup in which McDonald was clear on New Zealand mare Rising Romance halfway down the home straight and looking likely to win, only to be run down by Japanese raider Admire Rakti.
This time it will be the likes of The Cleaner in front with Criterion likely to be running at them strongly.
If Criterion wins there will be no time for McDonald to celebrate. Immediately after his last ride today he heads direct to Tullamarine Airport to catch a night flight to Singapore where he will ride tomorrow for Laurie Laxon.
One of his engagements is for the Laxon-trained Stepitup in the rich Raffles Cup.
Somewhat forgotten in the lead-up is New Zealand mare Silent Achiever, although she remains reasonably steady in the market around the $10 mark.
She has as much class as any in the field and trainer Roger James seems this week to be relishing the peacefulness of being the forgotten runner.
?It's been a ride Bruce Sherwin will never forget.
The Raffles Farm manager and racing manager for Malaysian businessman and thoroughbred breeder and owner Dato Yap Kim San will be trackside at Moonee Valley today, ideally to watch his greatest moment in racing.
Sherwin has already achieved much in racing. He raced NZ Oaks winner Vapour Trail and shared in group one star Shamrocker as well as rising to the top of the commentary ranks in New Zealand and Macau.
But Sacred Falls has been the ride of a lifetime, one which could yet reach its pinnacle in the Cox Plate (2040m) at Moonee Valley.
"It's been amazing. Just the transition from a young horse that showed potential to getting to the elite level and winning at the elite level. It's been an amazing ride," Sherwin said.
Consideration was given to retiring the dual Doncaster Hcp winner in the autumn but after his fast-finishing second to Dundeel in the Queen Elizabeth Stakes at Randwick in April, it was decided he would stay in training with Sydney trainer Chris Waller and target the Cox Plate.
Raffles has faith in Waller's ability to peak the O'Reilly entire for his target race, in Zac Purton's ability to guide on a trouble-free path to victory and most of all in Sacred Falls' ability and willingness to win.
"Everything has gone to plan. Judging by his win in the George Main Stakes two starts ago, we're sure he's improved again this preparation from the autumn," Sherwin said.
"The 2000m is a little question mark but he's in career-best form and he's going to be right in it."
Sacred Falls will spark massive celebrations at Waikato Stud, should he win today.
He was bred at the Matamata stud farm and the Chittick family have bought back into the stallion and have secured him for stud duties next year.
If successful he would join Savabeel and Ocean Park as Cox Plate winners on the Waikato Stud stallion roster. "The Cox Plate is the best weight-for-age race in Australasia and from a breeding perspective, it's a far more valuable race to win than the Melbourne Cup," Sherwin said.
"Sacred Falls is a true Kiwi horse. He's Kiwi-bred and Kiwi-raced and he's spent most of his life here.
"Tony Pike trained him early on and he spells here and goes to Tony for his pre-training before he joins Chris."
Sherwin, who called the trials at Cambridge on Thursday and was booked to fly to Melbourne yesterday, said he would try to keep his mind on other things in the lead-up to the race.
"I'll just keep busy and try not to think about it too much. There's nothing more we can do."
- Additional reporting NZ Racing Desk