Logician will face a maximum of 10 rivals when he puts his unbeaten record on the line in the William Hill St Leger at Doncaster.
The Frankel colt has been hugely impressive in winning each of his four starts to date and emerged as a red-hot favourite for the season’s final Classic with a comprehensive victory in the Great Voltigeur at York on his latest appearance.
Logician will on Saturday bid to provide trainer John Gosden with a fifth St Leger success – following his previous triumphs with Shantou (1996), Lucarno (2007), Arctic Cosmos (2010) and Masked Marvel (2011).
Aidan O’Brien already has six victories in the Town Moor showpiece to his credit, having struck gold with Milan (2001), Brian Boru (2003), Scorpion (2005), Leading Light (2013), Capri (2017) and Kew Gardens (2018).
The Ballydoyle handler has whittled this year’s potential team down to six, with Sir Dragonet and Il Paradiso his two chief contenders.
Sir Dragonet finished a close-up fifth when favourite for the Investec Derby at Epsom in June, but was beaten at odds-on when he returned from a midsummer break in the Royal Whip Stakes at the Curragh last month.
Il Paradiso, on the other hand, is set to line up off the back of a career-best performance in third behind star older stayer Stradivarius in the Lonsdale Cup at York.
The O’Brien squad is completed by Barbados, Norway, South Pacific and Western Australia.
Sir Ron Priestley has won five of his six starts this season – his only blip coming at Royal Ascot. Mark Johnston’s charge is unbeaten in three subsequent appearances and is set to step up to Group One level for the first time.
Martyn Meade’s Geoffrey Free winner Technician and Dashing Willoughby from Andrew Balding’s yard complete the acceptors.
Gosden is hoping the Doncaster showpiece will prove the perfect test for Logician.
“He has been in great form since York,” said the Newmarket trainer.
“He is a very relaxed character and he has a lovely big, long, loping stride. I thought (back in May) this might be a Leger horse.
“He has come a long way in a short time. The nice long straight at Doncaster should suit him well.
“But it will not just be Aidan and our one horse – there are other horses in play, and I’ve mentioned one that won at Goodwood (Sir Ron Priestley). It has more depth to the field than people are making out.”