The Curragh handler last clamied the prize with Big Break in 2013, and Yulong Gold Fairy (9-2) bridged the five-year gap with a game performance.
Shane Foley produced the three-year-old filly late on to hit the front, where she was all out to hold the Jim Bolger-trained Smash Williams by a head.
Flight Risk, also from the Bolger stable, was just half a length away in third place.
Weld sad: “This is the fifth time I’ve won this race in the last nine years. She loves that ground and is a very consistent filly.
“She won a big two-year-old race last year and won the Listed Corrib Stakes at Galway and has been multiple Group-placed and she is exceptionally brave.
“That’ll be it for her for the year and I’ll speak with her owner and hopefully she’ll stay in training next year.”
Weld was also responsible for fifth-placed Imaging, who was sent off the 11-4 favourite.
“I was very pleased with Imaging and match-fitness told on heavy ground,” he said.
“Declan ((McDonogh) said on the very testing ground he tired a furlong and a half down.
“He’ll go for the Knockaire Stakes at Leopardstown in two weeks’ time. I’m very pleased with him and he’ll be back to be a very decent horse.”