Emulous took within her stride the step up to Group One company with a superb performance in the Coolmore Fusaichi Pegasus Matron Stakes at Leopardstown.
The 9-2 shot was settled at the rear of the field by Pat Smullen, and still had all seven rivals in front of her rounding the turn for home.
But Smullen appeared to know he had plenty of horse underneath him and once he pushed the button, his mount found top gear to defeat the Ballydoyle pair of Together and Misty For Me in most impressive style.
It was a third successive victory for Emulous following a pair of Group Three triumphs at the Curragh and Fairyhouse.
Four-time Group One scorer Misty For Me was sent off the 6-4 favourite and while Aidan O'Brien's filly did little wrong, having been ridden positively, she was simply left in the winner's wake once the pace quickened.
Together finished second in the English and the Irish 1000 Guineas and again had to make do with the runner-up spot, some three lengths adrift of the brilliant winner.
Weld said: "It's lovely to train a Group One winner for Prince Khalid (Abdullah) and she (Emulous) has been very consistent.
"We've picked her races for her and she's won three Group Threes for us. I was always thought she was capable of winning a Group One.
"She's progressive and a very talented filly and we'll probably look at the Sun Chariot at Newmarket for her. We trained her for today and it's paid dividends."
Smullen added: "I always felt she was of that level, but that was a very hot race.
"It worked out beautifully for her in that they went enough pace that I could come from behind like I did with one run. She picked up very very well.
"She's a very good filly and she could have a good back-end."
Teddy Grimthorpe, racing manager for Prince Abdullah, said: "She travelled very well in behind and she picked them up almost for fun.
"She was in good shape for today - in a good frame of mind.
"She'll go for the Sun Chariot at Newmarket now."
