Quinz won the featured Racing Post Chase at Kempton this afternoon for trainer Philip Hobbs and jockey Richard Johnson.
Johnson tracked the early pace set by Safari Adventures and went to the front down the back straight for the final time.
Nacarat followed him into the home straight but was anchored by his big weight between the final two fences as Mount Oscar stayed on to challenge.
The 50-1 outsider looked set to score for Aidan Coleman but Quinz, giving Philip Hobbs a fourth win in the race, found plenty for pressure to score by a length-and-a-quarter.
It was eight lengths back to the gallant Nacarat in third with Hey Big Spender (12-1) fourth.
Sky Bet cut the winner to 10s from 14s for the Stewart Family Spinal Research Handicap Chase at Cheltenham.
Johnson said: “He’s really grown up and learnt a lot. It’s a very good effort to win a big handicap like this as a novice.
“He went chasing last year but I don’t think he was mentally ready. They have done a great job with him and brought him along slowly.”
Hobbs said: “It’s amazing really because last year he ran in two novice chases at Newbury and his jumping was moderate, but he is a different horse now.
“He is in the Grand National – Richard’s initial reaction was that it’s not a good idea but he would get in without a penalty and he’ll never get to run off a weight like that again.
“We haven’t put him in at Cheltenham as we are not sure it is a track that suits him.”
He added: “It’s just coincidence our record in this race and having the right kind of horse for it, nothing more than that.”