Jonjo O'Neill's Synchronised was a surprise winner of the Lexus Chase at Leopardstown under Tony McCoy.
The 8-1 chance tracked runner-up Rubi Light and Quito De La Roque into the home straight and swept clear in impressive style.
A fine leap at the last sealed victory and, with his rivals toiling, Synchronised bounded clear to score decisively.
Last season's Welsh National winner also had the option of defending his crown at Chepstow on Tuesday, but connections instead decided to go for Grade One glory.
As a proven mudlark, the JP McManus-owned eight-year-old looked to have plenty on his plate in the drying conditions.
However, he still produced a fine performance to beat Cheltenham Gold Cup hopes Rubi Light and Quito De La Roque.
Rubi Light was tackling the three-mile trip for the first time, having landed the John Durkan Memorial Punchestown Chase earlier this month.
But despite travelling strongly and jumping fluently, he had no answer when Synchronised came to challenge him at the top of the straight and was eight and a half lengths in arrears.
Quito De La Roque, the 13-8 favourite, was going for a sixth consecutive victory and was last seen beating Sizing Europe at Down Royal.
He, too, went well for a long way, but had to make do with third spot.
Frank Berry, racing manager to McManus, said: "That's brilliant, I couldn't be more delighted.
"Jonjo has done a fantastic job and he got a great ride.
"I thought the ground might be too quick for him but he handled it really well.
"In fairness, he ran well in his two hurdle races on good ground.
"He had 11st 11lb in the Welsh National at Chepstow and it was going to be a slog, so we made the decision to come here.
"I was a bit worried about the ground but we decided to take our chance.
"That gives us an idea of where we are going with him and we can look at some of the good races.
"He gets the trip and he jumps, and he'll get an entry in the Gold Cup.
"We'll leave it to Jonjo and we'll wait and see. He had a hard enough race there and more than likely will go straight to Cheltenham.
"He'll also get an entry in the English Grand National."