Grand National favourite Blaklion finished second as 8-1 shot Yala Enki claimed the National Trial Handicap in the sunshine at Haydock.
Only three of the eight starters finished the race over three miles four-and-a-half furlongs.
The Venetia Williams-trained eight-year-old Yala Enki mastered the heavy going to win by an emphatic 54 lengths.
Blaklion, trained by Nigel Twiston-Davies, was carrying 11st 6lb and was never able to seriously challenge.
With four fences to jump, Tom George’s Wild West Wind began to go clear but stopped abruptly and was soon pulled up.
That left Charlie Deutsch in prime position on Yala Enki, riding at Haydock for the fifth time, and the bay gelding surged to his first victory since March last year.
Blaklion, ridden by Sam Twiston-Davies, found his big weight in testing ground just too much, with Mysteree the only other finisher, a further 20 lengths adrift.
Twiston-Davies, who has been allowed by his boss Paul Nicholls to maintain the partnership with Blaklion in the National itself, said a combination of factors contributed to his defeat.
“He just got very tired. Carrying that weight in that ground took its toll and we just took him straight back to the stables,” he said after dismounting on the course.
Meanwhile, on soft ground at Ascot, Colin Tizzard’s 12-year-old Cue Card, bidding to become the first horse to win the Grade One Ascot Chase three times, was beaten into second place as Ruth Jefferson’s 2-1 favourite Waiting Patiently won by two-and-three-quarter lengths.
BBC horse racing correspondent Cornelius Lysaght
This was obviously an emotional win, coming so soon after Malcolm Jefferson’s death, but an outstanding one too by Waiting Patiently.
Though the formbook will say that the gallant Cue Card went down by only two and three-quarter lengths, the winner won with a deal of authority, moving so sweetly throughout.
Jefferson always insisted you are indeed best ‘waiting patiently’ with this type of horse to get the best out of them and to ensure longevity; with that in mind, it’s quite likely his entry in the Cheltenham Festival’s Ryanair Chase won’t be taken up.