Sir Mark Prescott's Alpinista ploughed her way through the mud at a wet ParisLongchamp to see off the late challenge of Vadeni in the Qatar Prix de l'Arc de Triomphe.
It was the culmination of a brilliant run of form for the grey daughter of Frankel, as she was winning her eighth race in a row, including a sixth successive Group One, and she had to show her customary guts and determination.
Luke Morris sat motionless in the slipstream of the tiring leader, Titleholder, heading into the final quarter mile and she skipped a few lengths clear when her jockey went for home on the far rail.
However, Vadeni emerged as a big threat in the closing stages under Christophe Soumillon, but Alpinista had enough left in the tank to win by a half a length.
Last year's winner Torquator Tasso ran another great race in a close-up third.
"It's absolutely marvellous," Prescott said. "It's an enormous relief.
"He [Luke Morris] has ridden for us for 11 years, Miss Rausing has had horses with me for 36. I trained her grandmother and it's hard to think of a better day.
"You felt she was always going to win but it's a relief. It's a wonderful change to have one that can really go and she has been perfect."
Morris said: “Things went lovely. They went a good strong gallop up front and it was nice and smooth. I was worried with the rain but she’s a remarkable filly, whatever the ground she’s so versatile and so tough.
“From stall six it made my job a lot easier than it could have been, I couldn’t believe how well she was going coming into the straight. I was taking her back two furlongs out just trying to conserve her energy as long as I could.
“When I needed her she dug in very deep for me, she was very tough.
“It’s the pinnacle of my career and it’s an unbelievably special day. I was having to hold back the tears. Sir Mark’s had an unbelievable effect on my career. He’s an unbelievable trainer and person and I’m so lucky to ride for him.”
Rausing dangled the possibility of a further run this year when she said: “She will come back to our stud next year. As for the Breeders’ Cup or the Japan Cup, we want to go home and talk about it.”
Georges Rimaud, racing manager to Vadeni’s owner, the Aga Khan, said: “We were very pleased with his run and we were obviously beaten by a very good opponent.
“Christophe (Soumillon) had a good run through the whole race and thought he was going to win, but the mare found more.
“He’s proved he stays the trip in soft ground, so we will go away and discuss what will happen in the next few days.”
Frankie Dettori said of Torquator Tasso: “He finished really strong and ran a super race. The draw didn’t help but it’s his style of racing to run on the outer.
“I thought for a moment I might get to them, but they were too strong for me.”
Aidan O’Brien confirmed the unplaced Luxembourg pulled a muscle.
“Obviously he got stuck in the ground, he pulled a muscle off his near-hip. He’s sore enough now,” he told Sky Sports Racing.
“He’s sore enough now, hopefully we can take him home but he’ll be sore enough for a while. It will heal in time and hopefully we can look forward to next season. I’d say that will almost certainly be it this season.”
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