Paul Nicholls is unable to put his finger on the reason Bryony Frost and Black Corton have gelled so well but the pair go in search of a seventh win together in the Sodexo Reynoldstown Novices' Chase at Ascot.
Given they have only teamed up seven times and met with defeat just once, and that last time out Black Corton won a Grade One, their success story has been one of the highlights of the season.
Black Corton, owned by Andy Stewart and Jeremy Kyle among others, began his season at Fontwell in June and his improvement has astounded Nicholls, although his task is made more difficult this weekend by shouldering a 5lb penalty.
"I got him beat at Newbury (only defeat under Frost) as I probably didn't have enough belief in the horse and we should have made more use of his stamina, as we did at Kempton," said Nicholls.
"Early in the season, one of his enthusiastic owners Andy (Stewart) said 'RSA' and he was right and has deserved to be in the race.
"This is really a prep race for Cheltenham - the plan is to go to Cheltenham after Saturday. The idea is to have him right for Cheltenham.
"He has just progressed, I don't know why. I was going to go to Cheltenham fresh, but he has had a nice break and he is so well. You are only a novice once and he will have to run in all the best races next season.
"I'm not sure why him and Bryony get on so well together, something just seems to have clicked with Black Corton this season and they've just been on a roll. One thing he has done is progress from race to race, and thrived on it.
"He astounded me in the Kauto Star, he went a right good gallop from the start, and kept going a good gallop. Sadly the horse from Anthony's (Honeyball, Fountains Windfall) fell four out, but Bryony was happy she was getting a lead and he galloped strongly all the way to the line.
"One thing he did do is when he sidestepped Anthony's horse, he pulled his front shoe off and pulled part of his heel off and finished lame. It would have stopped a lot of horses and he was in his box for 10 days after that with that nasty little injury, so he did well to win."
Nicholls added: "He is not a big, scopey horse like Denman. He is a small, athletic horse that has done really well. He has got to a rating that is quite lofty now and unless he progresses next year, it will be quite hard. But he has done nothing wrong - who knows, he is progressive and could be a surprise package for us.
"He is tough, jumps and Ascot on Saturday will be a nice race for him."
The Honeyball-trained Ms Parfois has been a revelation over fences this season and with her mares' allowance, only meets Black Corton 2lb wrong at the weights.
"If she reproduces her performance from Warwick last time I think she'll be hard to beat," said Honeyball. "Conditions are in her favour, her jumping has really come together and we've been looking at this race for a while.
"She hasn't won right-handed but she ran well in a Grade Two over hurdles at Sandown so I'm not worried about that, either.
"If she runs her race, I think she'll take all the beating."
With Cyrus Darius getting North Yorkshire-based Ruth Jefferson off the mark as a trainer on Thursday, the late Malcolm Jefferson's daughter sends two of her best horses south in search of big prizes.
Waiting Patiently runs in the Grade One on the card, while Mount Mews steps up in class after being beaten on his second start over fences at Doncaster.
"He's in good form and we'll give it a go," she said. "I suppose Black Corton is the one to beat."
Gary Moore's Crystal Las completes the field.