The St Leger and Breeders' Cup hero was produced by Ryan Moore to collar Tartan Bearer inside the final furlong as their stable companion Ask battled hard on the rail.
Conduit, 13-8 favourite, edged to his right and tightened up Tartan Bearer 100 yards out. But the 2008 Derby runner-up recovered to hold Ask by a head, finishing 1¾-lengths behind the winner.
After a stewards' inquiry upheld the result, Newmarket handler Stoute said: "It's nice to watch. I'm very proud of them - they've all run great races.
"They are top-class, lovely, sound horses and this is a bit special. We've been very lucky. We've been one-two in the Guineas and one-two in the Breeders' Cup."
Stoute collected £890,600 of the £1million prize-money on offer for his owners to effectively clinch his 10th trainer's title.
Conduit and Tartan Bearer are both owned by the Ballymacoll Stud, who picked up £782,900.
Peter Reynolds, racing manager for the stud, said: "That is our 50th Group One winner and Sir Michael's 10th individual and 20th overall Group One for Ballymacoll - which isn't bad.
"Lord Weinstock bought the place in 1960 and we have kept it going. We need days like today.
"Michael had the idea to run both horses for a while. Tartan Bearer was entered in the Group Two at Newmarket but Michael said we would go to Ascot.
"I wasn't that happy about it at the time but it is a great result."
William Hill make Conduit 8-1 from 14s for the Prix de l'Arc de Triomphe at Longchamp in October with Paddy Power going the same price from 10-1.
This article has 0 comments