Cirrus cloud hangs over Frankel’s toughest test in Champion Stakes
Frankel's team admit the threat he faces in tomorrow’s Qipco Champions Stakes at Ascot will be his toughest test to date when he comes up against last year's winner Cirrus Des Aigles.
The prospect of soft ground has put strains of fear into many of Frankel's huge army of followers, especially as the French raider is at home in testing conditions.
Whereas Frankel only ran for the first time over 10 furlongs in the Juddmonte International at York, Cirrus Des Aigles is as battle-hardened as they come - a fact which has not escaped Teddy Grimthorpe, owner Prince Khalid Abdullah's racing manager.
He said: "Cirrus Des Aigles has proved himself after the last two or three years. He's the defending champion and he came out at Longchamp and was very impressive in the Group Two.
"Certainly he's going to be a horse to be reckoned with."
Frankel does have one piece of form on soft ground, however, and whilst it was only in a maiden on his racecourse debut, he did beat John Gosden's subsequent multiple Group One-winner Nathaniel, who renews rivalry on Saturday for the first time since that race.
"He did it on soft first time out and has run on a variety of conditions," said Grimthorpe.
"He worked the other day on the racecourse at Newmarket, it could be described as soft that day, Shane (Fetherstonhaugh, work rider) got off and said he handled it very well."
Frankel's trainer Sir Henry Cecil has been fighting cancer throughout the summer but he has barely missed a morning on the gallops.
Perhaps ominously for his rivals, the 10-times champion trainer thinks the best horse in the world may be still progressing.
"I was very pleased with Frankel's final piece of work. He gives the impression that he is better than ever and still improving," said Cecil.
"I could not be happier with him. He seems full of himself and, considering the time of year, he is really good and healthy in his coat. He eats everything put in front of him.
"It will be a far from easy race with Cirrus Des Aigles and Nathaniel in the line-up.
"They are two good horses who will go in the ground and get the trip really well.
"They have to be really respected."
The one burning question after tomorrow’s race is whether Frankel will race again.
And while it is highly unlikely, a final decision has still to be made.
"It is entirely Prince Khalid's decision, he will make it in his own time," said Grimthorpe.
"He know this is a very public horse - he shares the horse with the public - but the decision is one he will make when he's ready."
In completing his perfect 13-from-13 record, Frankel sparked debate across the racing world as to which was his best performance.
Grimthorpe believes his seven-length victory in the Juddmonte International at York, when he was stepping up to a mile and a quarter for the first time, was his defining moment.
"I'm slightly biased, but I thought his last performance at York had all the ingredients for me - it was absolutely sensational," said Grimthorpe, who holds an executive position on the Knavesmire.
"As a two-year-old he started to prove himself exceptional and he's improved and blossomed into the horse we know.
"This year has proved how hard it is to get a top-class horse to the races.
"Henry has brought this horse 13 times to produce his best on 13 occasions.
"To have produced him without a blip is testament to Henry and his team."
Tom Queally has been the lucky man on board for each race but cannot pick out one particular highlight.
"York was a complete performance as he was completely professional," said Queally.
"The Guineas was breathtaking, it sort of had the 'wow' factor, but the Juddmonte and Queen Anne were equally as impressive.
"I've been in a very privileged position and he's been a huge part of my life.
"He's raised my profile and I'm delighted to have been associated with him."
Trainer Corine Barande-Barbe believes Cirrus Des Aigles may also still be improving, even though he is now a six-year-old.
She said: "Every race he has run in, he always seems to take one step up and he always seems to look his best when he tries something new.
"We ran him over a mile and a quarter in last year's Champion Stakes and we thought that was him at his best.
"Then we ran him over a mile and a half in Dubai, and it looked like that might be his best.
"Last year he wasn't even a Group One winner before the Champion Stakes. He won and he showed that the better the field, the better he is.
"Maybe he's still improving. On Saturday it could be the best in the world over a mile to middle distances against the best over 10 furlongs to a mile and a half.
"Whatever happens, it will be a great experience and we will enjoy it.
"If he wins, I will be pleased, but I won't be surprised.
"My horse has already been beaten and I know his level of ability.
"I'm not scared of Frankel."
Jockey William Buick is well aware of the task facing Nathaniel, who won the Coral-Eclipse at Sandown in July but was ruled out of the Prix de l'Arc de Triomphe after spiking a temperature.
"Nathaniel is a very good racehorse. He's had a fantastic season, and, like Frankel, will be having his last race on Saturday," said Buick.
"I'm trying to win. I'm not going out there to finish second but I'm going up against the best racehorse that people say they have ever seen.
"He's fighting for second, but we're not going into the race to be second.
"Obviously it's a big weekend and it's Frankel's last run, but it's a big weekend for Nathaniel as well because it's his last run.
"It was unfortunate that he missed the Arc, but he's fit and ready.
"He's still the horse that got closest to Frankel so we'll see if we can get even closer.
"He's an amazing mover, he floats up the gallops and covers so much ground.
"This year he has really excelled as a racehorse. He's shown his versatility as well and it would be very nice to finish off on a high.
"He's goes on all ground - he won his maiden on good to firm - he's very versatile."
One of the unknown contenders to many British racegoers is the German Derby winner Pastorius, whose trainer, Mario Hofer, said: "Frankel is in another world compared to our horse and I would be delighted if we made the first three.
"I am very happy with Pastorius and, without risk, there is no reward."
Trainer William Haggas also accepts Master Of Hounds, a recent Group Two winner in Turkey, is up against it.
He said: "It's a monumental task for him, but we are all privileged to be taking part.”