Apart from Camelot's attempt to become the 16th colt to win the English Triple Crown and the first since Nijinsky in 1970, the Group 1 St Leger could produce a statistic unique in Turf history. Victory in Saturday's race would make Aidan O'Brien the first trainer to win all five British classics in a single season.
Camelot has won the Group 1 Two Thousand Guineas and Group 1 Derby, and his Ballydoyle stablemates Homecoming Queen the Group 1 One Thousand Guineas and Was the Group 1 Oaks.
Unbeaten in five runs, Camelot will face eight rivals in the 236th running of the St Leger, the oldest and longest classic at upwards of 1 3/4 miles. He will be the first Derby winner to run at Doncaster since Reference Point, who in 1987 became the 35th Derby hero (including the 15 Triple Crown winners) to win both classics.
Camelot's class is not in doubt -- his official rating of 124 puts him 9 pounds ahead of the next best of his rivals, Thought Worthy and Main Sequence -- but he has yet to tackle further than 1 1/2 miles. But his late sire Montjeu is one of the world's leading influences for class and stamina, already responsible for two St Leger winners in Scorpion (2005) and Masked Marvel (2011), as well as a Group 1 Ascot Gold Cup winner in Fame and Glory.
O'Brien has won three St Legers, with Milan (2001), Scorpion and Brian Boru (2003). But the trainer with the best recent record in the race is John Gosden, who first scored with Shantou in 1996 and has won three of the last five with Lucarno in 2007, Arctic Cosmos in 2010 and Masked Marvel last year. He saddles three on Saturday -- Thought Worthy, Michelangelo and their pacemaker Dartford -- and success would make him the first trainer to achieve the hat-trick since John Scott in 1840.
Thought Worthy is the choice of stable jockey William Buick, who will be bidding to emulate Lester Piggott -- successful on Nijinsky, Athens Wood and Boucher -- as winner of three in a row. The only other rider to achieve the feat was Bill Scott, 1838-40. Thought Worthy, by Dynaformer, is a brother to Lucarno; previously six sets of siblings have won, most recently Ribocco (1967) and Ribero (1968).
"I left it late because I wanted to get a feel of just how both horses were at home, but it didn't make things any easier as John Gosden has them both primed to run for their lives," Buick revealed in his blog on Attheraces. "Michelangelo breezed on Tuesday and I gave Thought Worthy the same sort of spin on Wednesday and I couldn't split how well they were.
"In the end, it was the overall level of form that Thought Worthy has shown which swung my decision his way."
Michelangelo will be ridden by Frankie Dettori, who will be going for his sixth victory. He is already the race's most successful jockey currently riding and another win would put him behind only Scott (nine wins between 1821-1846), John Jackson (eight, 1791-1822) and Piggott (eight, 1960-1984) on the all-time list.
Like Lucarno, Thought Worthy finished fourth in the Derby and warmed up for the St Leger by winning the Group 2 Great Voltigeur Stakes.
"Although many thought we stole the Great Voltigeur, it was really down to his adaptability and courage," Buick added. "I think he's better judged on that performance than the Derby. I know Camelot is going to be very hard to get by, but both the Clarehaven runners have the ability to bustle him up and I want to be on the one that pushes him hardest and I think that's going to be Thought Worthy."
The Great Voltigeur has been the best trial for the classic in recent years, having produced nine St Leger winners since 1993.
Of those nine, Bob's Return (1993), Milan (2001), Rule of Law (2004) and Lucarno won both races. The most recent examples of horses beaten in the Great Voltigeur Stakes who turned the tables on their York conquerors to win at Doncaster have been Mastery (second at York to St Leger third Monitor Closely) in 2009 and Bollin Eric (third at York to St Leger third Bandari) in 2002.
Three behind Thought Worthy in the Great Voltigeur re-oppose in the St Leger, neck runner-up Main Sequence, third-placed Encke and Thomas Chippendale, fifth.
Main Sequence, a first St Leger runner for trainer David Lanigan, will be trying to become the first Derby runner-up to find compensation at Doncaster since Rule of Law in 2004. Guarantee, for William Haggas, and Ursa Major, for Tommy Carmody, are other first-time runners in the classic for their trainers.
"(Ursa Major) has improved and improved and although it's a big step up in class, he deserves his chance and he only has one shot at a classic," jockey Johnny Murtagh said. "We are here to win."
"He has improved with every run and we hope there is further improvement in him," said Tim Jones, racing manager to owner Andrew Tinkler. "It is typical of his breeding that he has improved as time has gone on. We are now throwing him in at the deep end on Saturday."
The Godolphin operation, previously successful with Classic Cliche (1995), Nedawi (1998), Mutafaweq (1999), Rule of Law (2004) and Mastery (2009), are represented by Encke.
Camelot has been eased to 2-5 favorite, from 1-3 Thursday morning, by the sponsoring Ladbrokes after eight rivals were declared to run against him. Two were taken out of the field at the final declaration stage, his stablemates Imperial Monarch and Chamonix.
Ladbrokes now offers 2-5 Camelot, 8-1 Main Sequence, 8-1 Thought Worthy, 12-1 Michelangelo, 14-1 Guarantee, 16-1 Ursa Major, 25-1 Thomas Chippendale, 33-1 Encke and 250-1 Dartford.
"The reason that we have eased Camelot to 2-5 is because the St Leger is a fantastic race for each-way punters with nine runners," David Williams of Ladbrokes commented, "and we expect most of the business from now on to be each-way bets.
"Camelot is trading at the biggest odds seen since midsummer."
After rain fell at the track Thursday, Doncaster's Clerk of the Course Jon Pullin had come under some fire for his decision to water ahead of the meeting.
"We had a warm, dry week last week and we were 25 (degrees) C on Saturday and Sunday, which was when we were watering," he explained. "On Sunday morning, we assessed the forecast and that was the first indication we had got of rainfall on Wednesday so we backed off the watering at that stage. No watering took place after Monday.
"Some of the jockeys reported that the ground was a bit dead after the first couple of races," Pullin noted. "It was not as warm today as had been forecast and I am leaving the going description overnight as good, good to soft in places.
"Tomorrow (Friday) is predicted to be dry. There is the chance of a light shower which should not amount to anything significant. Temperatures should reach 18 degrees Celsius which should help the ground dry out a bit.
"Conditions on Saturday should be dry, with temperatures warming up to around 20 degrees Celsius. If the forecast is correct, we should hopefully be racing on good ground on Saturday, St Leger Day."