Last year's winner Clan Des Obeaux has given trainer Paul Nicholls a record 11th victory in the King George VI Chase at Kempton.
Five runners went to the post for the traditional Boxing Day feature with Clan Des Obeaux taken on by his top-class stablemate Cyrname, Lostintranslation, Irish raider Footpad and outsider Aso.
Having inflicted a first career defeat over jumps on Altior at Ascot last month, Cyrname was the well-backed 5-4 favourite, with Harry Cobden siding with him over Clan Des Obeaux.
Cyrname adopted his customary prominent position in front with more than a circuit to go - and was still just about in front rounding the home turn.
But 11-2 chance Clan Des Obeaux was travelling the better of the pair in the hands of Sam Twiston-Davies and pulled away between the final two fences, winging the last to score by 21 lengths.
Cyrname boxed on to finish second with Footpad third.
"It's nice to have a one-two and it's nice for Sam to ride a Grade One winner," Nicholls said.
"I said all along it was a tough call for Harry. I couldn't really advise him what to do. When I said I don't know what I would have done I really did mean it - and I knew the more it rained today the more it would suit Clan."
Clan Des Obeaux could finish only fifth in last season's Cheltenham Gold Cup but Nicholls feels he could better that effort in March.
He is as short as 5-1 with some bookmakers for the blue riband.
Footpad's Irish trainer Willie Mullins watched from Kempton as veteran Faugheen turned back the clock to win the Grade One Novice Chase at Limerick.
"It is special to win a Grade One over fences with an 11-year-old as very few horses attempt it, but he hasn't much mileage on the clock and to me it is about mileage rather than age," Mullins said.