Magician finished second in the 1 1/4-miles heat in which Treve, last year's dominating Prix de l'Arc de Triomphe winner, was the overwhelming favorite. But Treve's rider, Frankie Dettori, said she "was never comfortable. I was following The Fugue, but struggling to keep up with her. I was never in my comfort zone."
It was the second straight loss for Treve, who came up narrowly short of Cirrus Des Aigles in her previous start and 2014 debut, the Group 1 Prix Ganay at Longchamp.
Trainer Criquette Head-Maarek said she had no immediate explanation for Treve's lack of a stretch run, but added, "Don't forget the winner today is a good filly, too."
That she is. The Fugue, a 5-year-old Dansili mare owned by Sir Andrew Lloyd-Webber and trained by John Gosden, finished second to Magician in last fall's Breeders' Cup Turf at Santa Anita. She went on to finish second behind Dominant in the Group 1 Hong Kong Vase at Sha Tin and then tossed in a clunker of her own in Dubai, finishing 11th in the Dubai Duty Free on World Cup night.
The Fugue finished third in this race last year, behind Al Kazeem and Mukhadram. Mukhadram finished fourth this time around, trained by Dank, the winner of last season's Beverly D. at Arlington Park and Breeders' Cup Filly & Mare Turf. Testimony to the quality of this year's Prince of Wales's: Mukhadram was coming off a runner-up showing behind African Story in the Dubai World Cup; Dank, off a third-place showing in the Dubai Duty Free.
"She proved today what she can do against top-class horses," jockey William Buick said of The Fugue. "When she gets an uncomplicated run, it's no bother to her. When she has a clear run at them she's lethal."
In other Royal Ascot races on Day 2, Wednesday:
Mustajeeb took charge late to win the Group 2 Jersey Stakes for 3-year-olds at 7 furlongs. Muwaary was second with Giovanni Boldini, second behind Outstrip in last fall's Breeders' Cup Juvenile Turf, landing third. Mustajeeb, a Nayef colt, is trained by Dermott Weld and Pat Smullen applied the winning ride.
Anthem Alexander captured the Group 2 Queen Mary Stakes for 2-year-old fillies, holding off Tiggy Wiggy to win by a neck. Newsletter was third. Anthem Alexander, a Starspangledbanner filly trained by Edward Lynam, posted her second straight win with Smullen making it a back-to-back double.
Integral broke through to victory in the Group 2 Duke of Cambridge Stakes for fillies and mares after two consecutive runner-up finishes. With Ryan Moore up for trainer Sir Michael Stoute, Integral raced close to the fore through most of the 1 mile, surged to command with a furlong left and won by 2 lengths over L'Amour De Ma Vie. Purr Along ranged up from last place in the big field to finish third. Integral is a 4-year-old Dalakhani filly.
Thursday's Royal Ascot card features the Group 1 Gold Cup at 2 1/2 miles with last year's St Leger winner, Leading Light, the leading contender among 15. Also signed on is Estimate, last year's Gold Cup winner and the 2012 winner of the 2-miles Queen's Vase. There's also the Group 2 Ribblesdale for 3-year-old fillies and the Group 2 Norfolk Stakes for 2-year-olds. In the latter, watch for the Aidan O'Brien-trained colt The Great War, a War Front colt who was the easiest of winners in his two previous starts, both in Ireland.