Sizing Tennessee led home a Colin Tizzard one-two in the Ladbrokes Trophy Chase at Newbury.
The 10-year-old was sent off a 12-1 shot, despite resuming with an 11-length victory at Fontwell in October, and he defied those odds to storm home by 10 lengths this time from better-fancied stablemate Elegant Escape.
Tom Scudamore had Sizing Tennessee in control by the last, having moved into a share of the lead with Dingo Dollar four out in a race run throughout at a hectic pace despite testing conditions.
Alan King's six-year-old eventually stayed on to finish third, a further seven lengths back.
An emotional Scudamore said: "I lost my grandfather two weeks ago, it was his funeral yesterday and I wasn't able to go - those are the sacrifices you make. I was so sorry not to be there, but he was with us today."
He added of the winner: "I was always confident in him, his novice chase form last season was very good and his Fontwell run has turned out well.
"I thought he was under the radar - I didn't expect to win like that, but a win is a win.
"I was always very happy and it was a great thrill."