Before there were international football teams, racehorses were proxies for national pride and aspirations. Gladiateur, the first French-bred winner of the Derby at Epsom in 1865, was dubbed “the avenger of Waterloo”, and even now, there can be times when old habits die hard. At 14.41 Pacific Time on Saturday, 21.41GMT in London and Dublin and 05.41 Japan Standard Time tomorrowon Sunday morning in Tokyo, the attention of tens of millions of racing fans across the globe will focus on Del Mar in southern California for a two-minute horse race, as City Of Troy, this year’s Derby winner, and 13 opponents go into the gates before the Breeders’ Cup Classic.

It is a race of champions from three continents, and for City Of Troy, as tough an away fixture as they come. He is attempting to complete an unprecedented double: no winner of the Derby, on turf, has ever added the Classic, on dirt, to his CV. And he is the only runner in the field with no previous experience on the surface. The fierce pace, the kickback and the gate speed of his rivals will be a unique, unrelenting test from the off. There will be no chance to ease himself into the contest, no mid-race lull to fill up his lungs.

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All of City Of Troy’s opponents are tried and tested on dirt, including Forever Young, the big hope from Japan, who was two noses away from becoming the country’s first Kentucky Derby winner back in May. Fierceness, the leading US-trained contender, is a multiple Grade One winner and came home six lengths in last year’s Breeders’ Cup Juvenile, the championship race for dirt-bred two-year-olds.

There is no real parallel elsewhere in sport for the challenge facing City Of Troy on Saturday. The tennis circuit moves from hard courts to clay or grass, but players know what to expect from each and never face a win-or-bust contest on a completely alien surface. They can also read the calendar, see when a change is coming and can prepare accordingly, both physically and mentally. In City Of Troy’s case, Aidan O’Brien, his trainer, needs to do the thinking for him.

“It’s a totally foreign game, a different continent, different surface, different pace of the race, different stalls,” O’Brien said at the track on Thursday. “It has to be a big disadvantage to a horse but all we can do is hope that he’s good enough to overcome all these things.

“We’ve done as much as we can do in our own part of the world. We didn’t want to go from grass straight to dirt, we wanted to try on an in-between surface so that he would get a chance to acclimatise rather than have it so dramatic that he’d be shocked. That’s why [his racecourse gallop at] Southwell [in September] was perfect. Everyone was saying that it wasn’t like dirt, which it wasn’t, but it was different to grass.”

When assessed on ratings, City Of Troy is, almost certainly, a better horse on grass than any of Saturday’s rivals are on dirt, and yet O’Brien knows better than anyone that it could well count for nothing.

The greatest European trainer of the last 30 years has sent 15 previous runners into the Classic on dirt, including another imperious Derby winner in Galileo, the sire of City Of Troy’s dam, Together Forever. All 15 have been beaten, including the “Iron Horse”, Giant’s Causeway, edged into second by the even grittier Tiznow in 2000, but the trainer calls City Of Troy the “best I’ve trained”.

“We’ve tried a lot and we’ve failed 100% of the time, so all we can do is learn from our weaknesses before and then hope that the horse is good enough to overcome the rest,” O’Brien says. “We’re trying it because it is possible, but he is a three-year-old and a baby and has to cope with all the adjustments.”

In one sense, perhaps, it is possibly for the best that City Of Troy is oblivious to how much is riding on his final run before retiring to stud. The $3.6m (£2.82m) prize for the Classic winner’s connections is small beer compared to the likely effect on the stallion value of both City Of Troy and his own sire, Justify, the most recent winner of the US Triple Crown – on dirt – in 2018. That could run to eight figures a year for as long as they are both at stud, which should be another dozen years at least.

O’Brien has done all he can to prepare his horse for his first and last race on dirt this weekend but even then, he cannot be sure that City Of Troy will not recoil from the Classic challenge as Galileo himself did back in 2004.

“He [City Of Troy] was always an aggressive horse from the gate and a high cruiser,” the trainer said. “There’s a lot of Justify in him, and there’s a lot of Galileo in him. I suppose the Galileo helps him to be as good on the grass as he is, and hopefully the Justify will help him to cope with the change.”

Forever Young can foil Troy glory bid

No one can know for sure whether City Of Troy will respond to the take to the dirt at Del Mar on Saturday in the style of Arcangues, the only previous European-trained Breeders’ Cup Classic winner on dirt, or Galileo, the 2001 Derby winner, who finished down the field.

What is certain, though, is that City Of Troy will be about 131 points shorter in the betting, with British bookies at least, than Arcangues, whose 133-1 victory in 1993 remains the biggest shock in Classic history.

Several firms claim to have seen significant backing for City Of Troy ante-post, but 15-8 still feels like a ridiculously defensive offer, which fails to account for the scale of the challenge facing Aidan O’Brien’s colt this weekend. Chelsea are only slightly shorter to win at Old Trafford on Sunday – a result that would surprise no one at all.

Any hesitancy at the gate or reluctance to face the kickback could be fatal for City Of Troy’s chance against seasoned rivals that know what to expect. So, while the heart would love to see City Of Troy head into retirement with an unprecedented Derby/Classic double to his name, the head says that he should not be such a clear favourite, and arguably not favourite, full stop.

Fierceness, the Travers Stakes winner, is an obvious alternative but his failure to run to form in the intensity of the Kentucky Derby earlier in the year is a nagging concern. Sierra Leone, beaten a nose in the Kentucky Derby, is also a live runner, but the most convincing alternative is Japan’s Forever Young (9.15pm).

He was another nose behind Sierra Leone in a three-way photo at Louisville, but that does not tell the whole story as the runner-up was leaning on Forever Young for most of the stretch.

Had he had a clear run, Yoshito Yahagi’s colt could well be going into the Classic unbeaten in seven starts, and his preparation since May has been structured entirely around Saturday’s race. With his Kentucky Derby experience to build on, Forever Young looks poised to give Japan its first success in the Breeders’ Cup’s showpiece event.

Wetherby 1.15 A 5lb rise for Tedley after a cosy win last time is offset by Jamie Brace’s 7lb claim.

Ascot 1.30 Paul Nicholls’s Samarrive has an absence to overcome but goes well fresh and has started to ease in the weights.

Wetherby 1.50 Anything close to Luccia’s Grade One form last year will make her very hard to beat.

Ascot 2.05 Master Chewy was touched off in a Grade One on his final start last year and sets out on his second season over fences on a handy mark.

Wetherby 2.22 An interesting switch back to hurdles for Twig, a winner first time up last season.

Down Royal 2.40 The Gold Cup runner-up, Gerri Colombe, looks set for a winning return to action in this race for the second year running.

Newmarket 12.00 Wild Angel 12.32 Luna Girl 1.07 Many A Star 1.42 Grecian Legacy 2.17 Plantadream 2.50 Smoken 3.27 Bolster 4.00 Tennessee Gold

Wetherby 12.40 Roadlesstravelled 1.15 Tedley 1.50 Luccia 2.22 Twig (nap) 2.58 Bravemansgame 3.32 Goblet Of Fire 4.08 Geryville

Ayr 12.48 Rock On Jet 1.23 Grand Voyage 1.58 Shoeshine Boy 2.29 Hello Judge 3.05 Dance Thief 3.39 Doyen Du Bar

Ascot 12.55 Star Of Affinity 1.30 Samarrive 2.05 Master Chewy 2.35 Tripoli Flyer 3.15 Secret Squirrel 3.45 Chianti Classico (nb) 4.20 Miss Ireland

Southwell 4.15 Sugarloaf Lenny 4.50 Cryptos Dream 5.20 Straight A 5.50 King Of York 6.20 Sky Advocate 6.50 Rousing Encore 7.25 Sardinian Warrior 8.00 Mae Amor 8.30 Drifts Away

Del Mar 19.00 Zeitlos 19.41 Cogburn 20.21 Thorpedo Anna 21.01 Emily Upjohn 21.41 Forever Young 22.25 Full Count Felicia 23.05 Mullikin 23.45 Porta Fortuna 00.25 Seize The Grey

Wetherby 2.58 With likely favourite Grey Dawning a non-runner, Bravemansgame can repeat his win in 2022.

Ascot 3.15 Secret Squirrel has scope for further progress in handicaps this season and was a winner first time up last term.

Ascot 3.45 Victory in the Ultima at the Festival capped a fine first season over fences for Chianti Classico and he remains on a workable mark.

Del Mar 8.21 The tough and reliable Thorpedo Anna looks poised for her sixth win of the campaign.

Del Mar 9.01 Being reunited with Frankie Dettori could be the final piece of the puzzle for Emily Upjohn.