London (AFP) - Two-time victor Altior has lost his tussle to be fit to defend his Queen Mother Champion Chase crown at the Cheltenham Festival, his trainer Nicky Henderson announced on Tuesday.
Altior had been found to be lame on Sunday but Henderson had seen a marked improvement on Monday.
However, the 69-year-old Englishman conceded defeat of getting him fully race fit on the eve of Wednesday's feature race in which the first prize is £225,000 ($290,000).
"Sadly we have had to finally admit defeat with Altior and therefore scratch him from the Champion Chase tomorrow," tweeted Henderson.
"This is really disappointing as the improvement yesterday was so encouraging that we were optimistic of getting there.
"That improvement did not continue last night and it is only fair to him and everybody else to reluctantly withdraw."
Henderson is determined, though, this will not be the end of Altior's season nor indeed of hopes of winning a third Queen Mother next year, which would give the trainer a record seventh win in the race.
"We will have to lend somebody else his crown," said Henderson.
In Altior's absence the six-runner contest looks to be a duel between English runner Defi du Seuil and Irish raider Chacun Pour Soi, bidding to give trainer Willie Mullins his first winner in the race.