• Hot favourite well beaten in major shock at the Festival • Ruby Walsh: he was lacking power jumping, which isn’t him

An explanation emerged here on Wednesday evening for one of the biggest upsets at the Cheltenham Festival for many years, when a post-race examination of Douvan, the beaten 2-9 favourite for the Queen Mother Champion Chase, found that the six-year-old was lame behind.

He was not obviously lame in the immediate aftermath of the race, which was won by the 11-1 chance Special Tiara, but Willie Mullins, Douvan’s trainer, suggested that an erratic round of jumping by his stable star, who was unbeaten in 13 previous starts for the yard, could be evidence of a physical problem that would emerge in due course.

Cheltenham Festival: Special Tiara sees off disappointing Douvan – as it happened Read more

Mullins said on Wednesday evening that Douvan was now “quite sore” and “we’ll get an X-ray and maybe an MRI scan done in the next couple of days”.

It was clear from an early stage that the race was unlikely to be the procession behind Douvan that his short price suggested. “He was lacking power jumping and he was jumping erratically, which isn’t him,” his jockey, Ruby Walsh, said afterwards.

Douvan reached for the third, ballooned the fourth and then put down and got too close to the fifth. He reached again to get over the eighth and was a beaten horse as Special Tiara led down the hill with three fences still to jump.

A crowd of 57,681, a record for the second day, applauded Special Tiara back to the winner’s enclosure – but Douvan was the horse many of them had come to see and there was general astonishment at his defeat. Douvan’s unbeaten record for the Mullins stable before this defeat included two victories at this meeting, in the Supreme Novice Hurdle in 2015 and the Arkle Trophy Novice Chase 12 months ago.

“When I saw him [over] those first fences, I said he’s going to have to be a super horse to win this,” Mullins said in the immediate aftermath of the race, “because you don’t get away with that sort of jumping and win Champion Chases. You might win a beginners’ chase or something like that but not championship class.

“When they jump like that they can injure themselves. It puts a huge strain on a horse his size and he put in two or three of those. I’d say he must have done something and it takes a lot out of a horse in the middle of a championship race.”

Mullins started the week as the odds-on favourite to finish as the leading trainer but left Cheltenham on Wednesday evening having drawn a blank on the first two days. Gordon Elliott, who is also threatening to depose Mullins from his long reign as Ireland’s champion trainer, has five winners after adding a double on Wednesday to his three-timer on Tuesday, while Nicky Henderson has three.

“It’s disappointing [to be struggling at the Festival],” Mullins said, “but I don’t think we were unlucky in any race yesterday, so I wasn’t too worried about that. Today, Bacardys [in the opening race] was nearly brought down at the first, and the [five] Coral Cup horses ran like they are, but this fellow is a big disappointment.

“I’m hoping that [Douvan] could be one of the best horses I have ever trained but today was clearly not his run. I am well used to dealing with the frustrations of racing, if not quite at this level with this type of horse, but that is the way that it is.”

Losing bets on Douvan were reported to include a single wager of £375,000, while William Hill suggested that the favourite’s defeat had been worth £10m to the betting industry and was “one of the best outcomes for bookmakers since the turn of the century”.

Facebook Twitter Pinterest Ruby Walsh bringing Douvan back after finishing down the field in the Queen Mother Champion Chase at Cheltenham. Photograph: Alan Crowhurst/Getty Images

Walsh and Mullins are still looking for their first wins of the week but Noel Fehily, the rider of Special Tiara, has now taken the feature event on the first two days of the meeting. He also rides Unowhatimeanharry, the hot favourite for Thursday’s feature, the Stayers’ Hurdle.

“I was wondering where Ruby was and thought he would be stalking me,” Fehily said, “but I got into a great rhythm down the back straight and my horse jumped better than he has ever done before. He’s a wonderful horse and deserved that because he’s been knocking on the door a few times [in this race].

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“It’s difficult to make all in the Champion Chase, especially going at that speed, and you’re worried you’re a sitting target for something else. When I jumped the ditch at the top of the hill, I thought Douvan might come past me but I didn’t think anything else would.”

Douvan’s defeat means that the much-anticipated meeting between Mullins’s horse and Altior, the winner of the Arkle Trophy here on Tuesday, in next year’s Champion Chase is in the balance for now.

Altior, though, is now the favourite for next year’s race in the long-range betting at a top price of 2-1, while Douvan can be backed at 3-1, a price that would have been difficult to believe five minutes before Wednesday’s race.

The one consolation that Douvan’s connections and many fans can take from the race is that a physical issue emerged that Mullins can now address. Douvan’s defeat was a huge shock but it was not evidence of a decline in his form, and there is every chance that he will return to his best next season. If so, the meeting with Altior will take on even greater significance, as it will give Douvan, and Mullins, a chance to set the record straight.

Thursday’s tips, by Chris Cook

Cheltenham 1.30 Yorkhill 2.10 Isleofhopendreams 2.50 Empire Of Dirt (nap) 3.30 Snow Falcon 4.10 Thomas Crapper 4.50 Titi De Montmartre 5.30 Southfield Royale (nb)

Chelmsford 5.45 Ebony N Ivory 6.15 Little Nosegay 6.45 Celerity 7.15 Just Us Two 7.45 Remember The Man 8.15 Intensical 8.45 One For Jodie 9.15 Royalistic

Hexham 1.45 Hurricane Rita 2.25 Topham Bay 3.05 Kanturk Bank 3.45 The Bishop 4.25 Finaghy Ayr 5.05 Acdc 5.40 Cougar Kid

Towcester 1.20 Goodnight Charlie 1.55 General Girling 2.35 Moidore 3.15 Socksy 3.55 Shelford 4.35 Viking Mistress 5.15 Toby Lerone