Hollie Doyle blog: Backing Pierre Bonnard to bag 10th Leger for O'Brien

Aidan O'Brien seeks a 10th St Leger title at Doncaster on Saturday, running four of the 11 runners, including the well-fancied Christmas Day and Pierre Bonnard; Hollie Doyle backing husband Tom Marquand to win Group Two Park Stakes (2.55)

Sky Sports Racing ambassador Hollie Doyle marks your card for the 250th St Leger and a stellar undercard at Doncaster on Saturday - live on Sky Sports Racing – and has a look at Leopardstown.

Who stands in the way of Aidan O'Brien and a brilliant 10th success in the world's oldest Classic, the Betfred St Leger Stakes (3.35) at Doncaster on Saturday? He saddles four runners on the 250th anniversary of the great race including probable favourite Christmas Day , who is bidding to become the first Derby winner to triumph since Reference Point 39 years ago.

Aidan's son Joseph O'Brien looks the most likely opponent to spoil the Ballydoyle party with the impressive Enceladus , who steps up to Group One company for the first time after excelling in the King George V Stakes at Royal Ascot and the Group Three Gordon Stakes at Goodwood.

However, I believe Aidan can complete the feat - not with Christmas Day but with his tough stable companion PIERRE BONNARD , who finished in front of him in the Great Voltigeur Stakes at York last month. This more demanding test of stamina is what he's been crying out for, and he can write his own piece of history.

GENTLE HURRICANE left his novice win well behind when chasing home Haffner in the Group Three Acomb Stakes at York last month and can go one better in the Betfred Champagne Stakes (1.45) on Saturday. Andrew Balding's colt will be very much in his comfort zone over seven furlongs at Doncaster in this Group Two and can put that experience to good use in an open renewal.

Likely favourite Desert Castle made a big impression on debut at the July Course in Newmarket when he shot to the head of the 2,000 Guineas betting, but this represents a big step up in grade which poses questions.

Meanwhile, Willie Muir and Chris Grassick pitch Breacher into this higher grade following his promising third in the Group Three Solario Stakes at Sandown - a run that entitles him to be in the mix.

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It just hasn't been MORE THUNDER 's year in top mile races but the return to seven furlongs in the Group Two Betfred Park Stakes (2.55) on Saturday can see him return to the winners' enclosure. He couldn't quite see out the trip after coming to win his race in the Prix Jacques le Marois last month but a strongly-run seven should play to his strengths.