Novice La Landiere registered her sixth consecutive win to score a comfortable victory in the Racing Post Chase at Kempton.
La Landiere left last year's winner Gunther McBride trailing in his wake
The eight-year-old mare, ridden by Warren Marston, was handy throughout and jumped into the lead three fences from home.
The 5-1 joint-favourite went on to win by three lengths to land the £58,000 first prize and give trainer Richard Phillips the biggest win of his career.
Last year's winner Gunther McBride, the other joint-favourite, had taken up the pace early on the second circuit but ran out of steam on the finishing straight and had to settle for second.
It was hard luck on jockey Richard Johnson, winner of the race for the last three years, who earlier in the week had rejected the ride on La Landiere to stay loyal to Gunther McBride.
"It didn't worry me one bit when Richard chose the other one - in fact he is
the worst judge since Judge Pickles," joked winning trainer Phillips.
"For 18 months we were really struggling with her but putting her over fences this season she has just kept on improving."
Winning jockey Marston said: "I was a bit closer to the pace than I wanted to be but three out I thought I
ought to go for it and she kept responding for me."
La Landiere will now head for the Cheltenham Festival, where she will run in either the Mildmay of Flete or the Cathcart.
Well Chief was another to boost his Festival credentials with victory in the Singapore Airlines Juvenile Novices'
The Martin Pipe-trained horse shook up the betting for the Triumph Hurdle after beating current favourite Saintsaire.
Ridden by Tony McCoy, Well Chief, who also holds an entry for the Supreme Novices' Hurdle at Cheltenham, took control of the race after the third-last flight and was thereafter never headed.
There were landmarks for two new trainers on Saturday's card at Kempton.
Grand National-winning jockey Richard Guest sent out his first winner as a trainer when 14-1 shot Mr Bossman won the Portlane Handicap Chase.
And Foreman was a first British winner for French trainer Thierry Doumen, better known as the jockey of some of his father Francois' horses, including Baracouda.
Racing Post Chase
1 La Landiere 5-1jf (W Marston)
2 Gunther McBride 5-1jf (R Johnson)
3 Ryalux 14-1 (R McGrath)
14 ran. Distances: 3l, 1l