The Keith Dalgleish-trained Kikini Bamalaam was the 100-30 favourite to follow up her course and distance success of three weeks ago, with Richard Fahey's Ventura Gold a 10-1 shot.
However, while bookmakers and punters apparently favoured the former, Ventura Gold carried the successful syndicate's first colours.
Middleham Park's racing manager Tim Palin said: "That was superb, apart from we seem to have messed it up with the caps!
"A girl in the office sorts the caps out and she has suggested in the past we should just do them alphabetically to avoid any confusion.
"However, I'm always keen to put the blue cap on the horse we feel has the better chance because of the photos after the race and things like that and today we felt that because he races more prominently, Ventura Gold might have the edge on a track like Musselburgh.
"Kikini Bamalaam is ridden from off the pace, but for whatever reason she clearly likes the place."
Ventura Gold hit the front in the final furlong of the second division of the Addleshaw Goddard LLP Nursery Handicap, but after a slow start, Kikini Bamalaam charged home under Connor Beasley to score by three-quarters of a length.
"She showed no ability whatsoever early on and was a bit wayward. We could easily have retired her after a couple of runs but we thought we'd persevere for a bit longer," Palin added.
"Because of that she probably came into handicaps fairly treated and the penny is starting to drop now.
"Ventura Gold is open to more improvement and we'd expect him to improve past the filly eventually."
Beasley went on to complete a double aboard Richard Guest's 5-2 favourite My Girl Maisie in the Tuv-Sud Handicap.
Trainer Ollie Pears and jockey Andrew Mullen combined to land the first division of the nursery with 4-1 joint-favourite Placebo Effect.
The most valuable event of the afternoon was the EBF Stallions Breeding Winners Fillies' Handicap, with victory going to the William Haggas-trained Tirania.
The 15-8 chance was last of the five runners on straightening up for home and had the door shut in her face on a couple of occasions when going for a gap.
However, once switched wide, she went through the gears impressively and was ultimately well on top as she passed the post three-quarters of a length clear of Peach Melba, who was the 13-8 favourite to secure her fourth successive win.
Haggas said: "She did it well and I'm pleased to get her back on track. It was my fault she got beat at Ascot last time. I ran her back too quick after her previous run at Sandown and the ground was a bit soft.
"I think we've learnt a bit about her today. She's quite adaptable, she's fine at seven furlongs and enjoys faster ground.
"We'll see where we go from here, but I'd like to aim a bit higher. If we can get some black type that would be great as she's quite a valuable filly anyway."
David O'Meara's Debawtry, runner-up on her Beverley debut a fortnight ago, went one better as the 4-7 favourite in the Witherbys Novice Auction Stakes under Phillip Makin.
Raselasad justified 6-4 favouritism for Tracy Waggott and Royston Ffrench in the Brown Shipley Handicap.
Mark Johnston's 2-1 shot Bonnie Arlene won the Dam Wealth Management Fillies' Handicap in the hands of Joe Fanning.
The concluding Scott Coppola Electrical Distributors Handicap went to Rebecca Bastiman's 14-1 shot See Vermont, ridden by Duran Fentiman.