The five-year-old joined Cumani’s yard over the winter after notching up a string of big-race wins in Australia but he had recently been sidelined by a stress fracture of his pelvis, which was discovered after a disappointing run in the Coral-Eclipse.
Starcraft was sent off at 13-2 to grab a first European slice of glory and jockey Christophe Lemaire had him smartly away and took up an early lead.
He was tracked by Cacique, Whipper and favourite Valixir but Starcraft never looked like being beaten as they turned into the straight.
Whipper soon faded out of it while Valixir found nothing under pressure and it was left to the fast-finishing Gorella to claim second, while the other British runner, Jeremy Noseda’s Majors Cast, was third.
Cumani’s charge was reversing form with Valixir after finishing third behind Andre Fabre’s charge in the Queen Anne Stakes at Royal Ascot at York and the Newmarket handler was thrilled to get a victory on the board.
“He is a very impressive horse,” said Cumani. “He is very powerful and the plan was to make the running if no-one else was ready to do so.
“He was given a great ride and the strategy was to keep him running and running.
“He was very impressive but he is a horse that I always knew had it in him.”
Lemaire was full of praise for Starcraft’s turn of foot.
He said: “As nobody wanted to take the lead I decided to go for it myself and he produced a brilliant burst of acceleration.
“It was a very good performance and he is a very impressive horse.”
Cumani now plans to go for the Queen Elizabeth II Stakes at Newmarket later this month before having a crack at either the Emirates Airline Champion Stakes or the Breeders’ Cup Mile, for which Coral make him a 7-1 chance.
Starcraft could face a re-match with second-placed Gorella at Newmarket and in America after the filly stepped up on her recent third in the Prix d’Astarte.
“That was an outstanding performance,” said trainer Jean de Roualle.
“To finish in front of such class horses is stunning and I feel very emotional as I am very close to this filly.
“It was a great ride from Thierry (Thulliez) and I must also pay tribute to her lad, Willy, who has almost gone mad looking after her.”
Nipping bounced back from a disappointing show at York last time with an easy success in the Group Three Prix du Petit Couvert.
Robert Collet’s filly could finish only 10th in the Nunthorpe Stakes but she was always travelling well in the five-furlong event.
The daughter of Night Shift, sent off the 5-2 favourite, took it up from the early leader, Miss Emma, at the two-furlong marker and eased away. British raider Maltese Falcon stayed on for second while Miss Emma was third.