Quirke's Gate became the meat in the sandwich among the pursuers and found himself with no room in fourth approaching the last.
Walhaan jumped it and came under a drive from Eoin Walsh with the pair appearing vulnerable to Horantzau D'airy who delivered his challenge under Paul Townend on the run-in.
Walhaan availed of the far rail. though, and found plenty for Walsh as Horantzau D'airy failed to get on terms with him. The 12/1 shot kept up the gallop to pass the post three parts of a length in front of the 5/6 favourite.
The gambled-on Star Harbour (33/1 - 16/1) brought home the each-way money for his backers in a keeping-on third, some four and a half lengths behind the runner-up.
This was Walhaan's third outing over flights having finished fourth in both Fairyhouse and Navan, but much closer on the second occasion. He was a long-standing maiden on the Flat.
Ciaran Murphy said: “It didn't go right for him in Navan the last day, but Eoin gave him a no-nonsense ride today, he was very good on him.
“We felt he had improved at home and we had this race pinpointed after Navan. A flat track on nice ground is really his thing.
“In fairness, he was going away at the line, from the second, and he's improving away. He's really starting to get the hang of hurdling now.
“We think there is a nice race on the Flat in him as well. We might mix and match or we might just stay hurdling and then go to the Flat later in the season.
“It's important he won for the lads (Ask Dot Syndicate) as they are good supporters of the yard, it's lovely to have a winner for them.”