"Done it" came only after McDonald worried himself close to an ulcer with 600m to run when Shez Sinsational looked to be in a near impossible position.
In direct contrast to McDonald's calm when his broken saddle on the way to the start held up the Auckland Cup for eight minutes.
McDonald was rushed back to the weighing room in one of the ARC's vehicles where another of his saddles waited, a quick jump on the scales and a dash back to the start.
There was nervousness all around, but McDonald looked as though he was walking to a beach picnic.
"Well, what are they going to do, start without us?"
In this case, hardly, but Integrity Unit boss Cameron George said later it is within the Rules of Racing to do so.
The riot would not have been worth it.
McDonald said the broken saddle was one he began his career with.
"I've been using it for five years and it has to break in this race."
McDonald's worry came when the field bunched at the 600m.
"I thought for a moment we were going to have a problem."
Shez Sinsational was a long way off the leaders at that point and McDonald knew he had to work the favourite into the clear.
"Once she gets into clear air she lets down beautifully."
For all that, Spiro broke clear early in the home straight and with only a few strides left Shez Sinsational had only drawn level.
But those who know the mare well knew those two strides were enough.
"When I really asked her she produced," said McDonald.
The "saddle dance" McDonald produced walking Shez Sinsational back down the victory lane of Ellerslie racecourse belied the tension of minutes before. There is still the main goal - the A$6 million-plus Melbourne Cup in November.
Yesterday's big race qualifies Shez Sinsational for the Melbourne Cup.
"I've also taken the option to nominate her for the Singapore Cup [2000m], which closed today. It's in May and if we change direction it's a race that could suit," said Sharrock.
"Four group ones this year and two to go," said an excited McDonald.
Those two are the $200,000 Diamond Stakes on Saturday when he will replace the suspended Matt Cameron on Rollout The Carpet and Scarlett Lady in the $200,000 New Zealand Stakes on the same programme.
Spiro fought bravely for his close second, but the rest appeared to have their chance. Six O'Clock News stuck on in the slightly rain-affected footing to take third ahead of Booming and Innocent Lady.
Rain set in one hour before the Cup, but the track, at that point in near perfect condition, held up well.
* The inquiry into McDonald's ride on Shez Sinsational in last Saturday's Nathan Memorial at Ellerslie was not concluded yesterday.
Stewards opened an inquiry when Shez Sinsational finished third to Jungle Boy. "It was not addressed today and will be dealt with on Saturday," said steward John Oatham.
