Ridden by Frankie Dettori who has now won the race a record six times, Enable travelled strongly throughout sat on the heels of the leaders and was sent for home as they entered the straight.
James Doyle settled his ride Sea of Class at the back of the field and looked to have it all to do as they came round the bend, but she yet again showcased her blistering turn of foot as she passed the whole field to set up an epic finish, but Enable held on to retain her crown.
Last years' runner-up Cloth Of Stars took third.
WOW! WHAT A RACE!— Timeform Live (@TimeformLive) October 7, 2018
ENABLE becomes the first British trained dual winner of the Prix de l'Arc de Triomphe!
Massive run from Sea of Class in 2nd coming from where she did!
Gosden said: "It's not been the preparation we wanted, it's been very difficult. I actually had a hiccup between Kempton and here with a slight temperature, so it has not been easy.
"She wasn't at her best today. I've had a difficult year with her and started with a bit more hair than I have now. It's entirely down to the filly and her guts and a lovely ride from Frankie.
"The ground is a little slick - I'd liked to have seen more rain - but she's got the job done and it's very much down to her mind and ability.
"She's a wonderful filly and it's an enormous sense of relief."
Gosden raised the possibility of Enable staying in training as a five-year-old in a bid to become the first horse to win the Arc three times.
He added: "It's great for Prince Khalid (Abdullah, owner-breeder). He wanted to come here and if she's in good form there's no reason you wouldn't try to come again."
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