Donna's Diamond provided trainer Chris Grant and jockey Callum Bewley with the biggest winner of their careers when gamely holding off the odds-on favourite Agrapart in Haydock's Betfred Rendlesham Hurdle.
The grey returned from a lengthy layoff with a course-and-distance win last month but that was in a handicap off a mark of 129.
Put into Grade Two company, he was taking on a real standing dish in these types of races in Agrapart, but Lizzie Kelly was sending out distress signals going down the back straight.
To his credit, Agrapart kept himself in contention but when Boite fell early in the straight, the race changed in complexion and it became a question of whether Donna's Diamond could keep going.
Backed from 14-1 to 7-1, Donna's Diamond did maintain the gallop to win by two and a quarter lengths from the favourite, producing a career-best effort at the age of nine.
Grant said: "When David Armstrong (owner) said he wanted to come to Haydock, I thought he meant for the handicap!"
Armstrong said: "The form of his last win has stood up and there was no fluke about it, I'm absolutely delighted.
"He had a big chip taken out of his knee, which is why he was off a year, and the vet did a great job.
"We've got to go over fences with him yet, but he's got the victory he deserved. He loves it here and deep ground suits."