James McDonald rates the next two weeks as the most important of his career and it all begins with It's A Dundeel at Moonee Valley on Saturday.

McDonald will ride the favourite in the $3 million Cox Plate - the first of several well-fancied mounts for him in some of the biggest spring races.

At 21, McDonald has an enormous weight of expectation to carry.

But he feels equipped to do it. Physically, mentally and emotionally.

"I rode in it (Cox Plate) last year, I've had experience in the Melbourne Cup, at Royal Ascot," McDonald said.

"I've been at the biggest meetings in the world. What's another race?"

He might sound flippant. McDonald is anything but.

Since he began his career in New Zealand he has been identified as one of the most gifted riders to emerge from his home country.

"I've got the biggest two weeks of my whole life coming up," McDonald said.

"I've got some great rides. One of the favourites for the Derby, one of the favourites for the Melbourne Cup, one of the favourites for the Cox Plate.

"I'm in a great frame of mind, I'm as fit as I've ever been, I'm as light as I've ever been."

It's A Dundeel has been McDonald's flagship horse.

He has ridden him in all bar one of his 14 starts and knows him better than most.

McDonald argues It's A Dundeel can adapt to any track condition and says the setback which forced a five-week break between runs is negligible.

"It won't matter. It will do him the world of good to have that space and he feels as good as ever," he said.

McDonald rode It's A Dundeel in a gallop at Moonee Valley on Tuesday.

Being a stallion, the horse doesn't overtax himself at exercise time.

"But wait until he gets the blinkers and a smack round the backside,' McDonald said.

It's A Dundeel delivered McDonald a win in one of Australia's most prestigious races in the autumn with his ATC Australian Derby victory.

On Saturday, they will be striving to win the country's best race.

"He's the best horse I've had an association with at the races," McDonald said.