Every year, one of the biggest storylines at the Melbourne Cup is the question of whether Irish trainer Aidan O'Brien can break through to win the race that stops the nation.

Like his arch-rivals at Godolphin, O'Brien has won countless elite races around the world — but both horse-training empires are yet to crack Australia's most famous handicap.

This year, O'Brien has the hot favourite for the Cup in Yucatan. Favourites don't have the greatest record in the Melbourne Cup in recent years, but the buzz is building around the horse who will be ridden by James McDonald next Tuesday.

At Werribee, 30 kilometres from the Cup venue Flemington, O'Brien's right-hand man, TJ Comerford, is the master trainer's eyes and ears as Yucatan and the other hopefuls The CliffsOfMoher and Rostropovich go through their paces.

Back in County Tipperary, O'Brien is based at his famous Ballydoyle stables next to Coolmore Stud.

The boss is a man with a legendary attention to detail — Comerford said O'Brien talks individually and as a group on the phone each day to all 10 riders for his horses in Australia.

Everyone is happy with how Yucatan is travelling right now.

"We're not here just for the good of our health," Comerford said.

"Aidan would like to win it [the Cup]. We've had enough goes at it [without winning] ... we're just hitting the crossbar."

"This [Yucatan] is probably our best chance for a while coming here to Melbourne.

"If we get the draw, I'd be quietly confident — we'll definitely run a big race.

"We'll definitely go close, but how close I'm not sure — [but] I'd rather be on him than any other horse at the moment."

Aidan O'Brien has not been back at the Melbourne Cup since controversy over his race tactics in 2008. ( AAP: Tracey Nearmy )

The desire and will to win remains strong, and Comerford is certain the breakthrough will come for O'Brien, to add to his triumphs at Ascot, the English and Irish Derby, the Prix de L'Arc de Triomphe, the Breeders Cup and the Cox Plate.

"Aidan O'Brien has won big races all over the world — if he could win this I'm sure it would be like a bug for him, that he would come back trying to win it again [and again]," Comerford said.

"It's only a matter of time before Aidan wins it anyway. It will happen."

One Cup worry over as Yucatan keeps its name

The Irish trainer is no stranger to Cup controversy, after a famous run-in with stewards at the 2008 Melbourne Cup over his race tactics on Septimus, Alessandro Volta and Honolulu.

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For whatever reason, he hasn't been back since — and a sighting of O'Brien at Flemington this year is unlikely, given the Breeders Cup is on in America over the weekend before the Melbourne Cup.

This year some controversy linked to an O'Brien horse has thankfully been sorted out before Cup day, as authorities have allowed Yucatan to run under its own name.

There is another Yucatan, who is trained in South Australia, and under Racing Australia rules O'Brien's horse was set to have a name change to Yucatan (Ire) for the Cup so punters would not be confused.

But after intervention from Racing Australia chief executive Barry O'Farrell, and local Yucatan trainer Matt Seyers giving his blessing, the rules have been set aside to allow Yucatan and the Michael Moroney-trained Sound Check to race under their original names.

Yucatan has been training well at the Werribee centre where the international raiders are stationed ahead of Melbourne's big races.

O'Brien senior trying to emulate his son in Cup

The O'Briens went 1-2 in last year's Melbourne Cup, with Rekindling (R) beating Johannes Vermeer. ( AAP: Tracey Nearmy )

Last year O'Brien was outdone — by family, no less — as his son Joseph trained Rekindling to win over Aidan's horse Johannes Vermeer.

It was nearly a year for O'Brien's stables at Ballydoyle, as Johannes Vermeer had finished third in the Caulfield Cup behind Boom Time.

"I think we won $1.3 million [in Australia] and we never won a race! It was a bit strange really," Comerford said.

So how did O'Brien senior — who first brought Yeats over as his first Cup runner in 2006 — felt about his son getting to win the big race before him?

"Joseph's been with us [at Ballydoyle] pretty much since he was born," Comerford said.

"While Aidan certainly wants to win the race, he's probably happier about it than you think.

"When it's one or the other of them [that wins] it doesn't really matter.

"If it's someone else, that's a different matter!"

Could this be the year?

Racing Victoria's general manager of international and racing operations, Paul Bloodworth, has watched the preparations on Yucatan, and like most judges he was extremely impressed with the five-year-old's brilliant win at Caulfield earlier this month in the Group Two Herbert Power Stakes.

Yucatan had the field strung out after the home turn, and he was eased down to win by a length after leading by six lengths 200 metres out.

Yucatan's easy win in the Herbert Power Stakes rocketed him to favouritism for the Melbourne Cup. ( AAP: Julian Smith )

"Anyone who saw Yucatan win the Herbert Power would have to say he would be very hard to beat for the Melbourne Cup this year," Bloodworth said.

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"I know TJ's been very confident in him all the way through from his quarantine back in Ireland, to here.

"He'd been telling anyone who'd listen that Yucatan would win the Herbert Power, and he was right on the money there.

"You just don't see horses win [Cup] lead-up races like that where they're throttled down in the last couple of hundred metres.

"James [McDonald, jockey of Yucatan] could have won by seven or eight lengths had he wanted to.

"I think if there's going to be a year for Aidan [to win the Melbourne Cup] this could be the year."