SSir Des Champs became Ireland's main contender for the Betfred Cheltenham Gold Cup when outstaying Flemenstar in the Hennessy Gold Cup at Leopardstown.
While the three-mile Grade One looks to have ended the Gold Cup dream for Flemenstar's connections, it is very much alive for Sir Des Champs.
After finishing behind Flemenstar in his two previous starts this season, Sir Des Champs came good to cement his place in next month's blue riband.
Both champion jockey Davy Russell and Sir Des Champs' owner Gigginstown House Stud were registering their first success in this race, as well as striking at the top level for the first time this season.
These races are second nature for trainer Willie Mullins, however, who enjoyed two other top-level wins on the card in a four-timer.
The winner's stablemate Quel Esprit, successful 12 months ago, set the pace in a four-horse affair but the race developed into a duel between the big two over the last two fences.
Andrew Lynch hung on to Flemenstar until after the last but he could not quicken to go past Sir Des Champs (11-8), who prevailed by a length and three-quarters.
Sir Des Champs is two from two at the Cheltenham Festival and was cut to 9-2 second-favourite with Stan James to make it a hat-trick in the Betfred Gold Cup, for which the Nicky Henderson-trained Bobs Worth is 3-1 favourite.
Mullins said: "He jumped well, did it well and it looks like there's more improvement.
"Every year he improves in the spring. He's been to Cheltenham twice and he loves the place.
"He loves that hill, so I'm hoping that he can show what he did the last two years, that he can keep improving coming into March.
"We were hoping he would do that at Christmas (in the Lexus Chase) but his jumping errors left him too far out of the race at the second-last.
"He got his jumping right today and probably the drier ground helped, plus there were only four runners and the one ahead of him (Quel Esprit) gave him a good lead.
"I thought he got low at the early fences and I thought to myself that he would have to improve, which he did.
"Davy was very good on him - he inserted pace four out when he looked around and saw that Flemenstar was going so well. He had to do that to win and make a staying race of it.
"The further he was going, I thought the better he was going."
Flemenstar could yet be seen at Cheltenham over a shorter distance in either the Queen Mother Champion Chase or the Ryanair Chase.
Francis Casey, assistant to his father, trainer Peter, told At The Races: "It could be a blessing in disguise, but I haven't a say (in what race he runs in at Cheltenham). It will be the owner and my father. I imagine he'd be going back in trip, but what race, assuming he is going to Cheltenham?
"I know father was always aiming at the Queen Mother and I have a slight preference for that myself.
"Today everything went right except for a few fences. He didn't stand off and didn't have the speed over them.
"He possesses a lot of speed and has a high cruising speed and jumping ability. Trying to extend it in longer races, he is not using his jumping ability.
"He was just popping his fences and everything was going to plan. We were hoping he'd get there, but it didn't work out.
"I'm delighted for the connections of the winner. I think Ireland needs a good Gold Cup horse and the way he jumped today they probably have a genuine contender, but I don't think that will be us.
"It proved conclusively he is not a three-mile horse. It's an extra two and a half furlongs in the Gold Cup and to me he'd struggle to get over the last."