Sir Des Champs survived a final-fence blunder to maintain his unbeaten record for Willie Mullins in the Growise Champion Novice Chase at Punchestown.
The six-year-old (2-7 favourite), stepping up to Grade One level after winning the Jeswon at the Cheltenham Festival, and also tackling three miles and a furlong for the first time, was sent straight to the front by Davy Russell and jumped accurately for much of the journey.
He had his rivals cooked rounding the home turn and as Russell just eased off his mount approaching the final obstacle, he ploughed through it, with the jockey doing well to stay on board.
With Mossey Joe suffering a horrific fall at the same fence when running a big race, hampering Frisco Depot, who unseated his rider, Sir Des Champs came home 36 lengths ahead of Shop DJ.
Mullins said: "Davy did very well to stay on and the horse was lucky enough to stand up. He was doing it well before that and we've always thought a bit about him. That's his first Grade One, so hopefully we can keep him sound and keep him right for next season.
"He's one of the best novice prospects I've ever had, but we didn't campaign him big. We just kept him down the country, but it's worked out nicely. We didn't learn anything today except the fact he did it over three miles. Davy thought he was just lazy and always had plenty in reserve, he was just cantering.
"He is a very relaxed horse and I think that will be a big help to him in his future career. We could maybe start him off here in the John Durkan Chase next season, but I haven't really thought about it too much."
Champion jockey-elect Russell added: "You are always told to be careful and if he had company he probably wouldn't have done that (made the mistake). I had the race in the bag and I didn't want to do the wrong thing. I thought I'd just go and pop it, but he's just left a leg in it.
"He gives you absolutely no feel - he's so lazy it's unbelievable. Willie has done a wonderful job with him and it's nice to have a horse like him to look forward to for next year. It's hard to know how much he'll improve."
Paddy Power left Sir Des Champs unchanged as 6-1 favourite for the Cheltenham Gold Cup, with Stan James at 5-1.