Jessica Harrington likened the Jockey Club Chase Triple Crown to "doing the lottery" as Sizing John prepares to take up the first of three challenges that could yield a £1million jackpot.
Last season's Cheltenham Gold Cup hero will edge closer towards winning the huge bonus if he can land the Betfair Chase at Haydock on Saturday and he's 3/1 with Sky Bet to deliver the goods.
Even still, Sizing John would only become a millionaire if he can claim the King George at Kempton and the Gold Cup back at Cheltenham in March.
Harrington said: "It will be very hard to win the three races. It's a bit like doing the lottery. If the first number doesn't come up you know your fate for the rest of them.
"I would like to bring him back to the Gold Cup, but the last two winners of that race (Coneygree and Don Cossack) haven't even got back to Cheltenham.
"From that point of view, plan A is to get him there, and anything else would be a bonus."
Sizing John's enterprising assault on the windfall was engineered by owner Alan Potts, who died last week at the age of 80.
Potts and his wife, Ann, who died in August, sent a strong squad of horses to Harrington's County Kildare yard in 2016 and the switch gained significant profit with two Cheltenham Festival winners in March.
Harrington felt the Potts' non-confrontational approach was a key factor behind their successful relationship.
She said: "Alan was the one who said last year that he would like to go for the £1million bonus this season. He was very good to me, and brought some nice horses into the yard.
"Everything I wanted to do, I was allowed to do. He was under a lot of stress with Ann not being well, but he got her to Cheltenham, Aintree, Punchestown and to France, which she loved, in June.
"She loved the horses and probably had more affinity with the horses than him. But, at the end of the day, if you said a horse can't run because he's not right he would never say run. He always put the horses first in anything he did."
Sizing John is likely to arrive in England on Thursday ahead of his first start since April, when he dramatically won the Punchestown Gold Cup. Harrington is, however, satisfied the seven-year-old is as fit as he can be without having had a run beforehand.
She said: "He's been to the Curragh to gallop around on the sand, to Naas and on Sunday to Punchestown. In Naas he went a full two miles over fences, and at Punchestown he galloped a mile and a half.
"My only worry is that three hard races last year might leave a mark on him, but he had a good few hard races the year before and seemed to come out of it very well."
Sizing John is one of seven confirmations for the Betfair Chase, for which Charlie Hall Chase winner Bristol De Mai is the ante-post favourite at 11/8.
Additional Irish interest comes in the shape of the Gordon Elliott-trained Outlander (10/1), who returned to winning ways in the JNwine.com Champion Chase at Down Royal.
Elliott said: "I'm very happy with him and he's in good form. It's a good race, but we'll take our chance. He had an operation for kissing spines after Cheltenham and sometimes if a horse has had a problem it can just take a run for him to think 'things aren't too bad'.
"A lot of people fancied him as an outsider for the Gold Cup last season, but he never jumped at all and I'd say that was his back. Forget about his run in Down Royal, if he comes back to his Lexus run he's good enough to line up in it. That was very, very good."
Cue Card, who is bidding to win the Betfair Chase for the third year running, is 11/4 second-favourite with Sky Bet, while the field is completed by Shantou Flyer, Tea For Two, and Traffic Fluide.
