Aidan O’Brien added another string to his challenge for the Derby here on Thursday when Circus Maximus ground out a one-and-a-quarter length win in the Dee Stakes, then set the scene for what could be the most significant Classic trial of the season as he revealed that Japan, a 7-1 chance for the Derby, could run in next week’s Dante Stakes at York.

Too Darn Hot, last year’s champion juvenile and 9-2 for Epsom, is among Japan’s potential opponents on the Knavesmire next Thursday, along with Godolphin’s Line Of Duty, last year’s Breeders’ Cup Juvenile Turf winner. If all three go to post, the winner could easily take over from Sir Dragonet, Wednesday’s impressive Chester Vase winner, at the top of the Derby betting.

Japan, who took the Group Two Beresford Stakes at Naas on the last of his three starts at two, is a son of Galileo out of a half-sister to the 1998 Arc winner Sagamix who cost 1.3m gns as a yearling. He had been expected to run in the Derrinstown Stud Derby Trial at Leopardstown on Sunday but is now more likely to travel to Yorkshire.

“The lads [in the Coolmore Stud syndicate] have decided to run Anthony Van Dyck [14-1 for the Derby] on Saturday [at Lingfield], Broome [10-1 for Epsom] on Sunday and if Japan doesn’t go to Leopardstown he’ll go to the Dante. It’s very possible that he could go to the Dante.”

O’Brien hopes to win the Derby for a record-equalling seventh time on 1 June, when Circus Maximus seems likely to be part of the Ballydoyle squad. He was cut to around 16-1 (from 33-1) for the Classic after his defeat of another O’Brien-trained runner, Mohawk, with the luckless Fox Chairman back in third after a difficult passage along the rail.

“Ryan [Moore, on Circus Maximus] said he was very happy at a mile-and-a-quarter but he wouldn’t mind stepping up if he needed it. The lads will decide what to do with all those things, but the first reaction is that [Mohawk] could stay at a mile-and-a-quarter but this horse could be a Derby possible.

“Ryan felt that there was a lot still in there. He’s lazy and I think he got left in front [too soon] but they’re better being a little bit lazy than over-racing.”

Jockey Jim Crowley looks across while waiting in the stalls at Chester. Photograph: Alan Crowhurst/Getty Images

O’Brien, who was not at Chester on Wednesday to see Sir Dragonet’s eight-length win in the Vase, added that no decision will be taken on whether to supplement the colt for the Derby until closer to the time. Sir Dragonet was promoted to second-favourite for Epsom after his win but has since supplanted Too Darn Hot at the top of the market.

Kew Gardens, who gave O’Brien his sixth win in the St Leger at Doncaster last September, was odds-on for his four-year-old debut in the Ormonde Stakes but finished a well-beaten second behind Andrew Balding’s Morando.

Morando, who relished the rain-softened ground, is a possible runner in the Group Two Hardwicke Stakes at Royal Ascot, while O’Brien is still aiming towards the Group One Coronation Cup at Epsom with Kew Gardens, who was giving 7lb to the field.

“Soft ground is not his thing,” O’Brien said. “It was a case of getting a run into him to get him started, and if he is well, we will think very hard about it [the Coronation Cup].”