Sametegal enhanced champion trainer Paul Nicholls' excellent recent record in the StanJames.com Supporting Greatwood Gold Cup at Newbury.
Nicholls had saddled seven of the previous 10 winners of the two-and-a-half-mile Grade Three and fired a twin assault at this year's renewal, with the Sam Twiston-Davies-ridden Sametegal joined by stable companion and 5-1 favourite Art Mauresque, the mount of Nick Scholfield.
Sametegal was a 7-1 chance on his handicap debut over fences, having filled the runner-up spot on his last two starts.
Twiston-Davies played a waiting game before unleashing his mount in the straight and the seven-year-old responded generously to his urgings after the final fence to score by four lengths.
Bennys Mist ran a fine race in second having forced the pace from flag-fall, with Aerlite Supreme taking third ahead of strong-travelling French raider Pythagore.
Tom Jonason, Nicholls' assistant, said: "This horse won at Huntingdon and has been a bit unlucky, but he's a classy horse and deserves a big win like this.
"I thought Sam gave him a peach of a ride and we're looking forward to him now.
"I'm hoping he gets in the two-mile-five-furlong race ( Brown Advisory & Merriebelle Stable Plate) at Cheltenham."