Last year's Queen Mother Champion Chase winner Dodging Bullets lost out to Top Gamble on his return to the track in the Betfair Exchange Chase at Newbury.
Top Gamble, the 11-10 favourite, made most of the running to continue trainer Kerry Lee's tremendous season.
He pulled clear under Richard Johnson to win by 10 lengths as his superior fitness showed.
"This horse loves really soft ground and stays very well," said Johnson afterwards.
"You thought conditions were slightly more in our favour if we were going to turn the tables on him [Dodging Bullets].
"Come March, on better ground, I'm sure Dodging Bullets is going to have a better chance."
Dodging Bullets, trained by Paul Nicholls, is around a 10-1 chance to retain his title next month with Irish challenger Un De Sceaux still the odds-on favourite.
Meanwhile, jockey Lizzie Kelly landed victory in Britain's richest handicap hurdle, the Betfair Hurdle, at the same track after guiding the 16-1 chance Agrapart to victory.
Kelly, who became the first female jockey to win a Grade One jumps race in Britain in December, had Agrapart, trained by her stepfather Nick Williams, well placed throughout and powered on to triumph by 11 lengths.
BBC horse racing correspondent Cornelius Lysaght:
Lizzie Kelly continues to be a breath of fresh air for jump racing, not only bringing considerable skills in the saddle - thriving, it seems, on stellar days like this one - but also masses out of it, increasingly capturing the racing public's imagination with her bubbly, articulate personality.
And she certainly knows how to play to the gallery, saying after her Newbury win: "I could run around this parade ring naked at the moment."
The growing profile of Kelly and other female jockeys and trainers are making a once male-dominated sport suddenly feel rather good about itself.