Jockey Russell steps in to ride L'Ami Serge at Doncaster

Russell – who won the blue riband race in 2014 on Lord Windermere – replaces Daryl Jacob who has opted to ride Gold Cup prospect Bristol De Mai at Cheltenham.

The veteran rider previously rode for West Witton trainer Ferdy Murphy before returning to his native Ireland where he is one of the most respected – and experienced – horsemen.

L’Ami Serge, winner of last year’s French Champion Hurdle and trained by Nicky Henderson, has finished second on his two starts over smaller obstacles this season.

However, this will be L’Ami Serge’s first start over fences in more than a year.

Anthony Bromley, racing manager for owners Simon Munir and Isaac Souede, said: “We feel it’s a good fit.

“Daryl was initially thinking of going to Doncaster, but we thought about it and Bristol De Mai is our highest-rated horse and he runs at Cheltenham.

“Daryl knows Bristol De Mai well, so we felt it was important he rode him.

“This is what happens on Saturdays and I’m sure there’ll be more clashes in the coming weeks.”

L’Ami Serge features in a 14-strong field, with Tenor Nivernais the only horse above him in the weights.

Alan King, who has won the prestigious contest for the last two years with Ziga Boy, relies on Label Des Obeaux, who was last seen pulling up in the Ladbrokes Trophy at Newbury.

Ziga Boy’s owners, the Axom syndicate, bid for a third straight success with another grey in Vibrato Valtat, trained by Emma Lavelle.

Paul Nicholls last claimed this prize with Big Fella Thanks in 2009 and is represented by Warriors Tale this time around.

Meanwhile, Flying Angel represents in-form trainer Nigel Twiston-Davies who said: “I don’t think he has run too badly at all this season.

“He must have a good chance and I am looking forward to seeing how he gets on.”

Yorkshire hopes rest with Sue Smith’s admirably consistent Wakanda who will be ridden by Henry Brooke.

Missing from the line-up is Malton trainer Brian Ellison’s Definitly Red who will put his Gold Cup credentials on the line by taking on the aforementioned Bristol De Mai in Cheltenham’s Cotswold Chase.

Meanwhile, fledgling trainer Richard Mitford-Slade is looking to Samuel Jackson to boost his already impressive profile in tomorrow’s River Don Novices’ Hurdle, Doncaster’s chief support race.

A former point-to-pointer, Samuel Jackson has won both his races under rules to date, the first at 100-1 at Taunton.

He proved this was no fluke by following up from a decent rival at Bangor earlier this month and fully warrants a crack in Grade Two company.

Connections of Thistlecrack are optimistic the headline-grabbing chaser could still be a potent force when he returns to action next season.

Colin Tizzard’s 10-year-old must miss the remainder of the campaign after he sustained a stress fracture of a leg in the King George Chase at Kempton.

Thistlecrack’s 2016-17 season also came to a premature end when he suffered a tendon problem that kept him out of last year’s Cheltenham Festival.

But Heather Snook, who owns Thistlecrack with husband John, has issued a reassuring update on his rehabilitation.

She said: “We don’t think he’s particularly unsound at the moment, but you’ve got to respect the X-rays and what the vets say.

“He doesn’t have many miles on the clock, so hopefully he’ll be okay. He’s still no age, so we would be totally optimistic with Thistlecrack, all things being equal.

“As far as his enthusiasm and him wanting to do the job, that won’t be a problem, but they are not machines and that should never be forgotten.

“We just count ourselves very lucky to have a horse who has reached such heights.”