After a false start to the Group One sprint caused by eventual third Jimmy Two Times crashing through the gate, Pasquier set his stall out to go all the way on Signs Of Blessing, who ploughed a furrow down the centre of the track.
But just as Pasquier's mount was putting his seal on things, Gold-Fun came down fatally 150 yards out, giving Christophe Soumillon a crashing fall from which he was lucky to walk away unscathed.
Meanwhile, although attacked on each side by Donjuan Triumphant and Jimmy Two Times, the ultra-game Signs Of Blessing knuckled down to score going away, building on his third in the Diamond Jubilee Stakes at Royal Ascot.
Rohaut outlined some ambitious plans for the winner that will take him out of France at least twice more this year.
He said: "We made the right decision to geld him last year, as he wasn't trying too much. The horse confirmed our judgement was correct with his good run at Ascot and has done well since then.
"Today he was able to quicken again from the front and when he does that it takes a good horse to get past him. Sprinters like this get stronger as they get older."
Rohaut said Champions Day at Ascot is on the agenda, adding: "If the ground is good he'll go for the big sprint at Ascot and then on to Hong Kong."
Connections of the Richard Fahey-trained Donjuan Triumphant were understandably delighted with his gallant effort.
Middleham Park Racing spokeswoman Sarah Davey said: "He likes a bit of cut in the ground and has run a cracker today. I would think his target will be the Prix de la Foret at Chantilly."
Dutch Connection charted a course along the stands rail under William Buick, but had a lot to do at halfway. Though making ground until inside the final furlong, his effort petered out and he just held on to fourth from Suedois.
His trainer Charlie Hills said: "He was stepping back in trip and has run a very good race considering I didn't think the draw was ideal and that he had a lot of ground to make up from halfway.
"Ideally the ground will be quicker if he comes back to France for the Foret. But the big target is the Breeders' Cup Mile at Santa Anita."
The much-travelled Gold-Fun was held at the time of the accident. It is thought the Richard Gibson-trained gelding broke both front legs.
Irish raider Gordon Lord Byron "wasn't on his A-game" according to jockey Richard Kingscote, who explained: "I was at him at the four pole and the horse I know wasn't there, although I don't know why."
Middleham Park went one better in the Prix de Reux when Ventura Storm put himself into the St Leger equation with a runaway triumph for Richard Hannon and Gregory Benoist.
Davey said: "He had to be ridden handily today and the way he's won under a great ride means he'll have Doncaster on his agenda as well as the German Leger.
"He's won two Listed races prior to this and looks better the further he travels. He likes soft ground and we have a lot to look forward to with him."
Listed - East Cape Guineas
G3 - Kings Cup
G2 - Resource Recycling Superstars Championship
G3 - Lamb & Hayward 4&5yo Trotting Championship
G2 - Storer Motors Nz Trotting Oaks