Neil Mulholland’s charge was winless after five previous outings over the larger obstacles, but had run some fine races in defeat, most notably finishing fourth in the National Hunt Chase at Cheltenham in March.
The eight-year-old was last seen chasing home Ok Corral – a winner earlier on the card – at Plumpton last month.
Last year’s winner Milansbar gave a bold sight in front for much of the three-mile five-furlong journey, but was a spent force racing down the back straight for the second time and Impulsive Star took the lead under Cheltenham Gold Cup-winning jockey Sam Waley-Cohen, carrying the colours of his father Robert.
Calett Mad and Crosspark both threw down strong challenges in the home straight, but Mulholland’s charge dug deep and saw off the former by three and a quarter lengths.
Mulholland said: “I’m delighted with him. He had a nice little pipe-opener round Plumpton the other day and obviously the winner of that race won earlier on.
“We knew he’d improve for the run, he had a light weight on his back and we felt he was on a nice mark.”
Impulsive Star is in line for another tilt at the National Hunt Chase at Cheltenham. Mulholland added: “He ran well in the National Hunt Chase last year and obviously he’s still a novice, so that’s the plan again.”
Nicky Henderson pointed towards a return to the highest level for Top Notch after he opened his account for the season in the 32Red Casino Chase at Kempton.
After suffering a bad reaction to a flu jab the popular eight-year-old only made his seasonal return last month when finishing third in the JLT Hurdle at Ascot.
Switched back to fences the Simon Munir- and Isaac Soude-owned gelding took a decisive step forward from his comeback as he found plenty to take the Listed prize by five lengths.
Meanwhile, Mercian Prince moved a step closer to a return outing over the Grand National fences at Aintree when jumping his rivals into the ground in the two-and-a-half mile chase under jockey Jack Quinlan.
Following this 17-length success, trainer Amy Murphy said: “The aim was the Topham. We might have ruined his handicap mark for that, but around Aintree it doesn’t matter. He jumped round in the Sefton like they were a lot of showjumps.
“That day it was heavy ground and it just caught him out after the (Melling) road.”
Brian Ellison has said Cheltenham Gold Cup contender Definitly Red will have a racecourse gallop at Sedgefield later this month before completing his big-race preparations with a piece of exercise at Wetherby on February 19.
The Malton trainer has decided not to give Definitly Red a prep race for the Gold Cup following high-profile successes in Wetherby’s Charlie Hall Chase, and the Many Clouds Chase at Aintree, under Danny Cook.
He is also hopeful, looking at the longer-range weather forecast, that conditions will be slightly quicker at Cheltenham in March than last year when the horse finished sixth in the Gold Cup on unsuitably soft ground.
Lady Buttons, a three-time winner for Catterick trainer Phil Kirby this season, is due to line up in a Listed Mares Chase at Huntingdon on January 25.
The mare, owned by Jayne and Keith Sivills, was last week handed an eyecatching entry in the two-mile Queen Mother Champion Chase at the Cheltenham Festival.
However, Lady Buttons will need a new jockey for her next assignment as regular rider Adam Nicol continues to recover from a broken leg suffered in a New Year’s Day fall at Musselburgh.
He has been in the saddle for each of the 24 races that Lady Buttons has contested under National Hunt rules, including all 11 wins.
Leyburn trainer Jedd O’Keeffe’s top Flat performer Lord Yeats was narrowly beaten by Encore Champs at Kelso.
The result was a rerun of the race at Wetherby in November when Lord Yeats, on his hurdling debut, had to play second fiddle to the Warren Greatrex-trained Encore Champs.
Lord Yeats, owned by Geoff and Sandra Turnbull, was then a wide-margin winner at Hexham.