The former Liz Doyle-trained 'pointer,' Al Ferof beat Walkon to lead home a grey 1-2 in the Paddy Power Gold Cup Chase at Cheltenham.
Paul Nicholls had never won the feature race at the Open Meeting but the Ruby Walsh-ridden seven-year-old moved well throughout and sealed the victory with good jumps at the last two fences.
Nicholls told Racing UK: "He goes well fresh, he always has done. On Thursday he worked as well as I have ever seen him work and I knew he had a chance, but he's always been quite a good horse. We'll have to think about Kempton (King George VI Chase) now. I always wondered if he would stay but he stayed well there and you'd have to say it might suit him."
Nicholls added: "He came in late because he cut himself in the field, but he had a gallop at Wincanton last weekend and went really well.
"The second-season chasers of ours like him are improving, I don't think the horses were right last year.
Owner John Hales said: "That was a stunning performance, as good as from any horse I have owned.
"The rain concerned me today, but I thought it was an outstanding run.
"I wasn't as confident when I started looking at the race yesterday - I thought it was going to be difficult to give weight away to horses like Grands Crus.
"I think we have decided we will go to the King George now, and he is a horse that we are going to have to look after."
Walsh said: "You need a bit of class in this race, which is why we were keen to take chance. In fairness to him we were forcing him at two (miles). Stepping up in trip is probably what we should be doing."
Alan King's Walkon (7/1) ran a blinder in second, only giving best up the run-in, Nicky Henderson's Nadiya De La Vega (12/1) plugged on for third, whilst Casey Top (40/1) fared by far the best of the Irish challengers in fourth.
Hot favourite Grands Crus travelled powerfully for a long way but the response when he came under pressuredown the hill was very disappointing and he weakened quickly.