Paisley Park won the Long Walk Hurdle at Ascot to give both trainer Emma Lavelle and jockey Aidan Coleman their first Grade One victories.
The six-year-old 8-1 shot triumphed in the three-mile contest, with Colin Tizzard's West Approach in second by a length.
Top Notch, trained by Nicky Henderson, finished third.
Previous winners Sam Spinner and Unowhatimeanharry both failed to complete the race.
"It's taken me too long, but it meant a lot to do it now," said Coleman.
"He's a star, he has a lovely way of riding. He's just a proper good horse."
Ten-year-old Unowhatimeanharry, trained by Harry Fry, fell and Joe Colliver was unseated on the Jedd O'Keeffe-trained Sam Spinner at the second hurdle after an enthusiastic start.
Owner Andrew Gemmell has mapped out Paisley Park's targets for the season.
Bookmakers have cut the horse's odds for the Stayers' Hurdle at the Cheltenham Festival in March to about 12-1 from 25-1.
Cornelius Lysaght, BBC racing correspondent
An amazing race really. What odds would you have got about the last two winners - Sam Spinner and Unowhatimeanharry - crashing out of the race, and the poor old favourite Call Me Lord found impediments following him around everywhere.
All that said, Paisley Park put previous troubles behind him - storming by West Approach after the last hurdle and putting himself on course for the Festival.
All involved were tasting their first Grade One successes, particularly surprising in Aidan Coleman's case as he's ridden more than 950 winners and is rated one of the country's best riders.
Valtor emerges as Grand National hope
Champion jumps trainer Henderson has never won the Grand National but appears to have a serious contender in Valtor afte the he won the Silver Cup at at odds of 33-1.
Valtor stormed to an eight-length win, under Welsh teenager James Bowen, from runner-up Jammin Masters.
The nine-year-old French recruit is now as low as 25-1 for the National at Aintree in April, having been available at 100-1 earlier in the day.
Bowen, 17, is the son of trainer Peter Bowen and younger brother of successful National Hunt jockey Sean Bowen.