ParisLongchamp's Arc card got underway in style as Ballydoyle's Diamond Necklace swooped to provide St Mark's Basilica with his first Group 1 winner in the Qatar Prix Marcel Boussac. Sent off the favourite for the first of the fixture's six Breeders' Cup “Win And You're In” races, the Listed Ingabelle Stakes winner who is a TDN Rising Star, presented by Hagyard, was always comfortable and when asked to mow down the Wertheimers' unbeaten Green Spirit (Kingman) did so without any need for the whip.“She's amazing,” commented a smitten Christophe Soumillon after steering the 11-10 favourite to a cosy length success. “I was very confident, she was my best ride of the weekend. The last time, she gave me a great sensation and was so relaxed going to the start and professional. She picked up so easily and it was just hands and heels only. She will be a great filly for next year, she is going to do something great.”Aidan O'Brien revealed that the 1,000 Guineas is the likely starting point in 2026. “A first [Group 1] for St Mark's Basilica makes it very special,” he said. “We were a little bit worried she was a little bit babyish to come here, but Christophe was adamant it would suit her. She's a lovely Classic filly and I'd say she'll be very comfortable starting at a mile and she will stay a trip I would imagine. She's very exciting and a typical St Mark's, every week goes by they're getting better and stronger.”DIAMOND NECKLACE WINS THE GROUP ONE QATAR PRIX MARCEL BOUSSAC! #QPAT pic.twitter.com/LJ6GxsPHGI— At The Races (@AtTheRaces) October 5, 2025The post ‘She Is Going To Do Something Great’: Soumillon Wowed By St Mark’s Basilica’s First G1 Winner Diamond Necklace appeared first on TDN | Thoroughbred Daily News | Horse Racing News, Results and Video | Thoroughbred Breeding and Auctions.